If premium cars turn you on, you probably like standing out from the crowd. But since everybody on your street already drives a BMW or Mercedes, and your company’s fleet manager is annoyingly negative about letting you have a Porsche or Maserati, what’s a person to do?

A person’s to choose a BMW or Mercedes that isn’t already clogging up the neighbours’ driveways, that’s what. Believe it or not, such a thing does exist.

What we have here is the BMW 4 Series Coupe, in 420d M Sport form, and its closest rival, the Merc C220 d Coupe AMG Line. As the first law of one-upmanship states, for every BMW there is an equal and opposite Mercedes.

They’re not entirely equal here as the only BMW we could get our hands on had the £1500 xDrive option. So, 4x4 versus 4x2, then. Talking of options, our BMW came on adaptive shocks and our Merc on air springs, so we’re none the wiser about what these cars are like without a pricey chunk of extra kit.

While we’re on the subject of equipment in general, both cars are appropriately generous. The differences are subtle – leather and xenons on the 4 Series, man-made leather and LEDs on the C-Class – but what matters is that you get all the obvious must-haves and plenty more besides.

Merc also chucks in a reversing camera, but what sets the C-Class apart inside is the overall brilliance of its cabin design. The dash is a proper eyeball-pleaser, all stylish design and classy materials – if you want a car that’ll make you feel good about yourself, it’ll do just that.

The 4 Series’ cabin feels stronger, however, and while both are equally spacious up front it gives rear-seat passengers a better deal. It has a bigger boot, too, and – no small thing – a much better multimedia system.

You’ll find yourself needing a bit of in-car entertainment, at any rate, as both cars bend your ears with some gruff diesel noise when the right foot goes down. The Merc is ultimately more refined, thanks to better vibration control and less intrusive engine noise at higher speeds (an extra ratio in the auto box helps), but neither truly excels.

The air-sprung C-Class tested here dishes up the best ride, too, dealing with broken surfaces with all the compliance you’d hope for. Putting it into sport mode turns it into a horrible bouncy thing, however – even though it has softer suspension which means more body roll. It’s a classic case of for horses for courses: the C-Class rides better, the 3 Series handles better, with a tautness that keeps it forever composed. We’d absolutely not choose the xDrive option, though; it ruins the car’s handling by stripping its front end of its natural agility, and despite its more wayward body the Merc steers better and turns in with more alertness.

At least being all-wheel drive helps the 3 Series out-drag the C-Class as tested, even though the latter has a bigger engine. More important, indeed, is what happens at overtaking speeds – where the Merc pulls better, and more responsively, from low down.

We’re not entirely comparing like for like here, clearly, but all we can do is test what we’re given. And the BMW we were given would cost a company car driver about £2500 more in tax over the course of three years. For private buyers, the C-Class costs less, has more kit and will be worth more when you sell it – though if you’re finance it, the difference is only slim.

All this points to one thing: the C-Class is the better car here. By giving us an xDrive model to test, BMW more or less guaranteed that.

Even without all-wheel drive, though, we think the 3 Series would come second to what is a very capable, comfortable, classy coupe that costs less to own than its image would have you believe. It’s not the keen driver’s choice, but the C-Class is strong in almost every area.

Specifications: BMW 420d xDrive M Sport Coupe auto (4 stars)

Engine size 2.0-litre, diesel

List price £38,685

Target price £34,747

Power 187bhp

Torque 295lb ft

​0-62mph 7.7sec

Top speed 142mph

Official fuel economy 60.1mpg

True MPG 44.1mpg

CO2 emissions 125g/km

Specifications: Mercedes C-Class Coupe C 220 d AMG Line auto (4 stars)