The Mercedes C-Class has traditionally campaigned in offering all that its brand knows about luxury saloons distilled into smaller form and in its first two decades of life, over 8.5 million global buyers happily bought into the concept.

For all that though, this was in truth for too many years a car a little short on quality and a little long on price tag.

It may have been good enough to account for 20% of total Mercedes sales but that wasn't enough to prevent it still always lagging a distant third in the compact executive sector sales charts behind its arch-rivals, BMW's 3 Series and Audi's A4.

In 2014 though, we got a very different C-Class, this fourth generation version designed to change the status quo in this segment and redefine what a car of this kind should be. That was a big ask, but there was a greater level of focus with this 'W205' model series C-Class than with any of its predecessors.

These were often trying to be too many things to too many people.

If you bought one, it was usually for a 'quality feel' rather than because it was the best contender in its segment to drive, the nicest to sit in or the cheapest to run.

With this MK4 design though, things changed.

In the 2014-2018 period we're looking at here, it was to this C-Class that aspiring middle management executives turned first in their search for something different from - and possibly a bit nicer than - their usual 3 Series or Audi A4 choices. There was certainly more than enough reason for them to seriously consider this car in its fourth generation form.

It was slightly bigger and a lot more advanced than the previous model and boasted the nicest cabin you could have in this kind of model.

But more important than all of that was the way that this 'W205'-series model's advanced hybrid aluminium structure brought the significant weight savings which made possible some of the lowest running costs in the segment.

This then, was the C-Class that BMW and Audi always feared Mercedes would build.

It sold until 2018 when it was heavily facelifted, but it's the earlier version which sold between 2014 and 2018 that we look at here as a potential used buy.

You don't really have to know very much about cars to recognise a MK4 C-Class.

And if you know the Mercedes model range beyond this car, it's probably fairly obvious where the inspiration for this fourth generation design came from.

By and large, customers come to this model seeking a scaled-down version of the brand's S-Class luxury limo and with this 'W205'-series design, the long bonnet, the set-back passenger compartment and the short overhangs are just a few of the things delivering exactly that.

The result might not please those who've just spent their lottery winnings on a top S-Class model but buyers browsing in this car's less exalted market segment will surely see it as a very desirable-looking thing indeed. Wander round the shapely silhouette and you quickly appreciate the painstaking attention to detail that's gone into things like the wafer-thin shut lines and the intricately formed jewel-like headlamps with their optional LED illumination.

There's real classic elegance here too, centred in profile around a waist-level character line - what Mercedes rather awkwardly calls a 'Dropping Line' - that descends discreetly from the front to a rear section where a pronounced shoulder above the back wheel gives the rear end of the car a power-packed look that's emphasised by softly sculptured LED rear tail lights.

More important than all of this though, is of course what sits beneath the shapely bodywork - specifically a structure with an aluminium content which with this MK4 model rose massively, from 10% to nearly 50%, resulting in an overall weight-saving of more than 100kg. One of Mercedes' original marketing slogans for this car was that it sat 'one class higher' and that's true not only in terms of style but, arguably, also in terms of size.

Almost everything with this 'W205'-series design is, after all, a little larger than it was before.

Partly that's because back in 2014, the brand's introduction of their only slightly smaller CLA-Class four-door coupe model gave this 'C' licence to grow a little within the bounds of what was possible before it intruded into Executive-sized E-Class territory - something the designers only just avoided.

Even as it was, this car's extra 95mm of length and extra 40mm of width made it as spacious inside as E-Class model from the late Nineties. That's something most obvious from a seat in the rear.

True, the sweeping roofline you duck around as you get in suggests that headroom will be at something of a premium for taller folk - and indeed it is once you get yourself inside.

Otherwise though, genuine improvements really were made here in terms of rear seat spaciousness in comparison to the previous model.

Where before, it wasn't really possible for one six footer to sit behind another in real comfort, the extra 80mm this fourth generation model boasts in its wheelbase length changes that.

It's not even quite such a squash to take three folk on short trips, should the need arise. But it's the up-front experience that really sets this fourth generation C-Class apart, not only from its predecessor but also from its immediate period rivals.

This, more than anything else, is the thing that will sell this car.

Come to the wheel familiar with the old pre-2014 MK3 C-Class model (which had a functional cabin that was about as stylish as Angela Merkel) and you'll find this car radically different, with a broad eye-catching centre console sweeping between the front seats.

It's a one-piece design on automatic models, but go for a rarer manual gearbox variant and you'll get the steeper dash with separate trim elements that's necessary for ergonomic operation of the shift lever.

Either way, one thing's for certain: you'd have to get a really plush rival BMW 3 Series or Audi A4 for it to feel anything like as nice inside as a C-Class.

There are none of the cheap plastics that on those cars, you can find hidden in the lower reaches of the fascia if you look hard enough and this Mercedes, the quality touches - things like the high gloss black trim on the centre console and the Artico man-made leather on the instrument panel - deliver much of the feeling of class upgrade that the brochures promised.

Original buyers had the option of beautifully veneered wood and even a lovely analogue clock if they wanted it.

Proper luxury then: just distilled into a slightly more compact form. Not that the practicalities were forgotten.

There's much more room to stow stuff around the cabin than there was on the previous MK3 model for example: take the door bins - nearly four times larger than before.

And, with these sorts of cars, we rarely feel that enough time has been spent on perfecting the seats, given the many hours owners will be stuck in them.

The front chairs on a 'W205'-series C-Class though, feel genuinely more comfortable than anything else in the segment from this period can provide, with extra shoulder support and another 10mm of height adjustment over what was delivered before.

As you'd expect, the driver's seat positions you beautifully in front of the leather-trimmed three-spoke steering wheel with its 12 multi-function keys.

Behind it, there's the brand's usual 'Direct Select' gearchange stalk for automatic models and a smartly efficient pair of 'tube design' round dials separated by a 5.5-inch TFT colour display, the combination of which is a model of clarity.

One other nice touch you might not notice: there are no stereo speakers in the doors.

Instead, using what Mercedes calls its 'Frontbass' system, they're mounted in the foot wells, installed in cavities that act as resonance chambers and give you clearer, crisper sound. Look around you and the two staples of modern Mercedes cabin style are present and correct.

There are five round SLS supercar-style air vents with metallic cool-touch finishing and above the three in the centre sits a prominent iPad-style infotainment screen, its free-standing positioning smacking either of after-thought or inspired design, depending on your point of view.

It's 7-inches in size as standard and acts as the display for the rather old-fashioned graphics of the Garmin sat nav system that most original customers specified.

Try though, and find a car whose original owner opted for something a bit more sophisticated in the form of the COMMAND online package that gets you a much more sophisticated 3D presentation on a larger 8.4-inch screen.

Either way, the functionality is controlled not only by the usual rotary controller that swivels, slides and pushes but also by a touchpad that permits letters, numbers and special characters to be handwritten.

An electronic handbrake switchin this MK4 design replaced the awful old foot brake of the previous model. And out back? Well, once you raise the boot lid, you'll find a 480-litre capacity - about the same as is offered by obvious rivals from this period.

There's a small ridge near the bulkhead that can sometimes get in the way if you're trying to slide stuff right back and use the whole one-metre length but overall, we'd say that the space on offer here is a little more easily accessible than it is in a 3 Series or an Audi A4 from the 2014-2018 period- easily wide enough for a set of golf clubs. If you need more room and have a model with the split-folding rear bench that Mercedes rather meanly deleted from the entry-level version, then you can use two provided levers to drop the 40:20:40 split-rear seatbacks and accommodate longer items, though if you going to be carting such things about regularly, the estate version would of course be a better bet.

The boot of this variant may not be much bigger (it's an unremarkable 490-litres) but you can free up 1,510-litres when the split-folding rear bench is pushed forward, potentially at the push of a button.

Please contact us for an exact up-to-date valuation.

We found plenty of satisfied C-Class customers, but also a few rogue examples.

Software problems cropped up quite frequently in our survey.

In one case, the car had to limp back home with its owner on reduced power.

In another, the auto 'box refused to change up higher than 3rd gear.

The Audio 20 navigation system is notoriously slow; try for a car with the much better COMAND navigation set-up fitted instead.

A few owners complained of creaks too - from the dashboard, the roof lining, the sunroof and the door seals/ door cards; look out for this on your test drive. Insist on a full Mercedes dealer service history, especially for the most recent models whose lengthy warranty - effectively for the life of the car - is dependent on proper servicing by an authorised agent.

Check that all the accessories work and watch out for cosmetic damage which can be expensive to correct.

These are popular family cars, so check for wear and tear in the rear.

Also look for the usual signs of wheel kerbing and poorly repaired accident damage.

(approx based on a 2014 C220 CDI - Ex Vat) An air filter is around £50.

An oil filter costs in the £6 to £11 bracket.

Front brake pads sit in the £30 to £60 bracket for a set (pricier brands £80-£100), while rear brake pads cost around £25-£66 for a set.

Rear brake discs can cost as little as £51-£84 (but up to £180 for pricier brands).

A headlamp is £170-£270; a tail lamp costs around £247.

A clutch kit is around £264; a thermostat is around £88.

There are all kinds of reasons why this 'W205'-series car is a more involving thing to drive than its predecessor.

First and foremost, it really ought to be sharper, thanks to the fact that its structure contains five times more aluminium than before.

That took over 100kgs from this fourth generation model's total kerb weight and gave it a lower centre of gravity.

Secondly, as a driver, you've all the necessary tools to make the most of this newfound appetite for corners, thanks to aluminium-fashioned rear wheel drive architecture.

And 'Agility Select', Mercedes' version of the 'drive select' and 'Drive Performance Control' drive mode systems you respectively find in rival Audis and BMWs. Here, as there, use of this system enables you to tweak steering feel, throttle response and auto gear change timings through various stages.

'Comfort' or 'Eco' if you're in a relaxed mood: 'Sport' or 'Sport +' if you're pushing on.

And 'Individual' if you want to set up the various system parameters yourself.

As with rivals, you can use the same settings to adjust ride quality too - though only if you get a car whose original owner opted for air suspension.. Fewer changes were made under the bonnet with the original version of this MK4 model.

The 2.1-litre diesel that almost all buyers chose continued pretty much as it was in the previous generation design, originally badged 'BLUETEC', then simply 'd'.

As with the MK3 model, the majority of customers wanted the 170hp version of this powerplant - the C220 BlueTEC model.

Like the entry-level C-Class derivatives, the 114bhp 1.6-litre C200 diesel and the 184bhp 2.0-litre C200 petrol, it came as standard with a six-speed manual transmission but most buyers chose to take up the option of the brand's familiar 7G-Tronic Plus 7-speed automatic gearbox with its steering wheel-mounted paddleshifters, another carry-over from the previous generation car. We can see why this C220 BlueTEC variant was so popular.

There's 400Nm of torque, so strong pulling power right down low in the rev range whenever you want it and decent performance, with the rest to 62mph sprint accomplished in 7.7s on the way to 145mph.

It's certainly worth the premium over the much feebler and smaller Renault-derived diesel in the entry-level C200 diesel C-Class.

In fact, our only real issue with C220 BlueTEC motoring is that the age of this car's engine tells when it comes to refinement: direct rivals are quieter.

In fact, you'll discover just how quiet this Mercedes can be if you take a drive in the impressively silent C200 petrol model, which is pretty much identically as quick as this C220 BlueTEC and efficient enough to make clued-in customers think twice about diesel if their annual mileage isn't very great. If you'd like to stay with efficient four cylinder C-Class motoring but have it delivered with a touch more power, then a couple more auto-only derivatives with the 2.1-litre diesel engine beckon.

The conventional choice is the C250 BlueTEC variant, which has 204hp at its disposal, so the 0-62mph sprint time is improved to 6.6s and the top speed rises to 153mph.

The same stats in fact as are returned by the less conventional choice, the C300 BlueTEC Hybrid, which uses the same diesel engine but mates it to a 27bhp electric motor so that thankfully, you hear a bit less of it.

It's what Mercedes calls a 'mild hybrid', which means that its electric-only range capability is very restricted.

If you want more of that, then you'll need to find yourself the rare Plug-in Hybrid C300e model - but that uses petrol power. And further up the range? Well, the engine choice is dominated by desirable turbocharged petrol power, with turbo four, twin turbo V6 or twin turbo V8 engines.

It is of course a V8 that's fitted to the flagship C63 AMG model, a gloriously sonorous 4.0-litre powerplant tuned to produce well over 500bhp in the top C 63S.

That C-Class derivative showed just how much Mercedes had learnt in recent years about handling dynamics - but even an ordinary 'W205'-series C-Class model demonstrates that to some extent.

What you learn after a spirited drive is that the Direct-Steer electric power steering still needs a touch more feel but that overall, this car is certainly more agile through the turns than it used to be - and even more so if you've one of the more powerful variants fitted with 4MATIC 4WD.

It all means that the gap to the class-leading BMW 3 Series was certainly closed here, if not completely overcome.

Thanks for this was due both to the weight-loss programme and a torque vectoring rear brake system that seamlessly applies slight brake pressure to the outside rear wheel during tight cornering to help get the power down where it's needed through the bends. The exact level of handling sharpness you can have will inevitably be heavily influenced by whether you've bothered to click into either the 'Sport' or the 'Sport+' modes on the Agility Select driving system.

And, more fundamentally, by the suspension choice fitted to the variant you're looking at.

We've already mentioned the AirMATIC air-sprung set-up.

If you can't stretch to that, then there are three options.

Standard is a Comfort Suspension package, but you can get that set-up lowered by 15mm if you go for a 'Sport' model - or stiffened if you choose an 'AMG Line'-trimmed variant.

In all three cases, there's a balance between feel and fluidity that we think works well. It's also hard not to be seduced by the technology here.

For example, from sat nav data, this car knows when you're about to enter a tunnel and automatically closes its air recirculation flap to stop the cabin getting filled with fumes.

At night, if you got a car with the 'Adaptive Highbeam Assist Plus' package fitted, you'll never have to dip your full beam in the face of oncoming traffic thanks to the clever way the system masks out any other road users detected in the beams' cones of light.

And of course, like most modern executive cars, this one can brake for you to avoid accidents at high or low speeds and to some extent, even steer and park itself.

It used to be quite easy to pigeonhole the three main premium contenders in the compact executive sector.

A BMW 3 Series gave you a sporty drive, while an Audi A4 offered a nice cabin and a bit of hi-tech.

If you went beyond these two and considered a Mercedes C-Class at all, you were probably a more mature buyer with priorities that didn't really fit into either category.

It was a bit of a compromise, badge equity choice.

But it isn't in this 'W205'-series MK4 model form. Potential Audi customers will like the high technology - the intelligent headlamps, the class-leading safety kit and so.

Wavering BMW buyers may be tempted by neat Agilty Select performance driving system and the unique air suspension option.

And both groups will appreciate the far-reaching running cost savings that in day-to-day terms, made ownership of the Three Pointed Star in this sector surprisingly affordable.

Find a well looked-after example and you'll enjoy this car very much.