New Mercedes M-Class review

* Merc's new big 4x4 tested * Price: 45,000 to 65,000 (est) * On sale: April 2012...

New Mercedes M-Class review

What is it? It's the new Mercedes-Benz M-Class, tested here in the United States ahead of its arrival everywhere bar the UK in the autumn. British buyers must wait until next April, when Merc's big 4x4 will arrive equipped with either a 3.0-litre V6 turbodiesel (tested here), or AMG's 5.5-litre, twin-turbocharged V8.

Mercedes UK is also considering selling the ML250 CDI, powered by a 2.1-litre, four-cylinder, twin-turbodiesel; it seems like a no-brainer to us. A diesel hybrid version is also in the pipeline; expect it in autumn 2012.

The new V6 diesel is the same size as the old one, but it's a very different motor. The engine now has 255bhp and 457lb ft of torque; the outgoing ML350 CDI has 228bhp and 398lb ft. Despite the gains in power and torque, the new engine - which is now mated to Merc's latest 7G-Tronic Plus transmission - delivers much-reduced CO2 emissions (179g/km instead of 235g/km) and up to 10mpg more, at 41.5mpg.

What's it like to drive? Impressive, while focusing squarely on further improvements to the values for which the M-Class is already known. That's to say that the latest generation is still not going to frighten BMW's X5 for agility or driver involvement; Merc's offering prefers to compete on comfort and refinement, and it does that very well.

The motor is very quiet during the vast majority of scenarios; push it hard and you might hear a distant, slightly gruff rumble, but at anywhere from urban pace to a motorway cruise, it's hard to hear at all. The increased torque is available from far enough down the rev range to allow swift progress without much effort.

The stop-start system - present as a part of Merc's Blue Efficiency package - is ultra-quick and extremely smooth. You'll barely notice the motor firing back up again.

The standard chassis set-up includes steel springs, but our car came with the optional height-adjustable Airmatic suspension. The ride was composed on Montana roads, although we'll wait until trying the car on rougher UK terrain before giving it full approval. Other chassis options include the Active Curve System, which controls the front and rear anti-roll bars to reduce body roll without impacting on ride quality.

The electric power steering system could be more communicative, but it's nicely weighted and accurate.

What's it like inside?The M-Class cabin needed an overhaul - particularly in its choice of finishes and plastics - and the new version delivers it. The new fascia looks imposing and plush, with lots of leather, wood, soft-touch plastics and double stitching.

Mercedes Comand infotainment system is managed by a rotary controller on the centre console, and other key switches - including those for the car's off-road programmes - are well positioned. Mercedes has also moved its multi-function stalk controller behind the steering wheel, making it a little easier to find.

Should I buy one? You can't yet - and there's likely to be a slight price increase to compensate for the extra kit, improved efficiency and new technologies. However, we'd say that if you value refinement and comfort over B-road thrills, and you're able to hang on until April 2012, Mercedes latest offering should be worth the wait.

Porsche Cayenne

What Car? Says