It's chuffing excellent. There you go Top Gear-heads, an instant, internet-friendly verdict on the new BMW M5. Go spread the news far and wide.

Of course there's more to it than that, so let's expound a bit. This is BMW's most powerful production car ever, a 552bhp business express with all manner of trick bits hidden away - including, for the first time in any M5, a pair of turbos. This has been a bone of contention for the purists and you can understand why. A forced induction engine doesn't - indeed can't - respond as purely, accurately and immediately as a naturally aspirated one. But BMW has gone to great lengths to make this twin turbo 4.4-litre the best it can be.

And the best it can be is really quite something. It develops 501lb ft of torque all the way from 1500-5750rpm, which means that after a fractional delay when you put the hammer down it really doesn't matter what gear you're in, what revs you're at, or how big that overtaking gap is. The M5 will punch right through it.

At first you're simply happy to drive around marvelling at the mid-range grunt. Then you remember that the redline doesn't cut in until 7200rpm, so you really ought to check out the upper reaches. A wise idea. Once past 4500rpm, the M5 is downright astonishing. It hits supercar hard - so hard that orange lights start to flicker and power is cut when travelling in a straight line. That'll be the wheels trying to unhook themselves from the tarmac's tenuous hold then...

Time to disable the traction control and while you're there, fumble with the buttons around the gearlever, have a fiddle with the settings for the throttle, steering, suspension and gearbox. Each has three settings (basically comfort, sport and extra-sport), but the middle of each with maybe the sportiest throttle is about right for road driving.

That does depend where you're driving, of course. Stick the M5 in comfort mode across the board and it does a damn fine impression of a 530d, all quiet and cruiser-y, lapping up motorways with a remarkably adept ride and imperceptible gearchanges. Even the engine is muted. But that's not what the M5 is for, so you'll inevitably up the ante with the switches until you arrive at something that can scare you half to death. One tip: don't turn off the traction control unless you have a lot of space to play with.

This would be a problem, were it not for the fact that by super-saloon standards the fifth generation M5 is beautifully balanced and pliable. The brakes have their work cut out, but the chassis works both ends evenly: you can dive into corners with confidence and come out the far side knowing how much you can open the throttle before the rear end starts to send itself sideways. Again. Little bit of criticism for the steering, though. You always know where you are with it and there's oodles of reassuring weight, but actual feel? Not really, not through huge 265-width front tyres in a car that has to cope with 1870kg of bulk. Nevertheless, you can drive it hard, really hard and it won't bite - it's too well-mannered for that.

And that, in a small way is a drawback. Despite the acceleration it delivers and the speed it carries, this is not a raw, animalistic car, even with all the buttons turned up to 11. The standard 5-Series is a big, heavy, insulating machine and the M5 is the same. It can't quite shed that cosseting feeling: this is an M5 that's aimed primarily at businessmen who like driving, rather than drivers who do the business, if you see what I mean. The last generation M5 was a rabid V10 thing, all fury and attitude and nothing like any other 5-Series. The new one has more in common with the only other V8 M5, the E39 that launched in 1998 - it's a gentler, more approachable car and far easier to live with every day. Maybe that's not a bad thing - it probably opens the car up to a wider audience.

Now, the question of design: is the M5 just a little too understated? It's a big car, most notable for its road-filling width. Blue brake calipers are new and there are the usual unique wing mirrors, quad exhausts and gaping grille, while the cabin has a smattering of M badges to go with the extra buttons. By gum it's well built and attractively designed inside, though.

A few other things worth mentioning: the noise of the V8 is bassy, very bassy, with a shrill turbo whistle overlaid. It's good and meaty but doesn't have the glorious exuberance of a Merc E63, for instance. It can also be driven economically (well, 25mpg is actually achievable, but then so is 10mpg). And there's a rumour that M division might be working on a manual gearbox option, chiefly for the US market. Even if they are I'm not sure I'd have it - the seven speed double clutch tranny is brilliantly accomplished.

And that neatly sums up the whole car. M's engineers have obviously felt the weight of expectation pressing down on them - a new M car is a rare and special event after all - and so they've honed and polished the M5 to a considerable degree. The result is mesmerizingly fast and beautifully judged, but you'll have more pure fun and enjoyment in a 1-Series M Coupe.

We like: Ability to pulverize supercars while carrying four in massive comfort. Smokes tyres like you wouldn't believe.
We don't like: lacks the fire and brimstone delivery of the last-gen M5
The verdict: A hugely accomplished super-saloon and a worthy addition to the annals of the M5
Performance: 0-62mph in 4.4secs, max 155mph, 28.5mpg
Tech: 4395cc, V8, RWD, 552bhp, 501lb ft, 1870kg, 232g/km CO2
Tick this on the options list: 20-inch M double-spoke wheels, £2,080
And avoid this: Night Vision system, £1,510