hey say revenge is a dish best served cold. To Mercedes, revenge is a dish best served in 2,800kg helpings. When the Mercedes M-Class was first launched in 1998, it was the big 4x4 to be seen in for all of a few months, before being ruthlessly bettered by first the BMW X5 and then by the Volvo XC90, the Volkswagen Touareg, the Porsche Cayenne and even by the Land Rover Discovery. It's not often that Mercedes accept such a situation and the tables have been well and truly turned with the latest M-Class, a car that makes its rivals look a little old hat. The ML350 represents the entry-level petrol model and taken in isolation looks a decent buy.

TThe trouble is, we don't buy cars in isolation. We compare, contrast and make value judgements. After assessing the competition, you may well decide that an M-Class is the best luxury 4x4 you're likely to encounter for £36,710. The complication comes when you add another fiver to that price tag and factor in the ML350's sibling, the diesel ML320 CDI. There's no getting away from the fact that for most of the people most of the time, the diesel M-Class is the better buy. Refuel the two cars and you'll make that fiver back and more in terms of fuel efficiency with the diesel model and that's before we've even taken into account the emissions ratings for company car buyers. Were the ML320CDI three or four thousand ponds dearer, the comparison would have been touch and go. As it stands, Mercedes look to have priced the ML350 out of contention.

All of which is a shame, because there's a lot to endear the ML350 to any luxury 4x4 buyer. Take that engine for a start. In many ways, the ML350 acts as a timely reminder that despite the massive popularity of diesel engines in this corner of the market, there's still a place for a well engineered petrol powerplant. This unit is becoming a Mercedes mainstay, having already been plumbed into the S Class, the SLK, the SL, the C-Class, the E-Class and the CLS, so it's a known quantity. Familiarity has bred anything other than contempt, however, as this engine proves to be one of the best of its ilk anywhere. It's the engine that turned the SLK into a Boxster rival and which made petrol-powered S Classes relevant again.

"The ML350 offers a silky alternative to the rather more obvious diesel option"

Drive is transmitted to bitumen via a seven-speed automatic. Stay with us, here because the automatic is no ordinary slushbox. It's got more in its locker than mere wafting, and with seven ratios to blur between, you're always plugged right into the meat of the torque curve. The column-mounted Direct Select shifter takes a little getting used to and points to the M-Class' American heritage, but if you're set to do a fair degree of traffic-bound commuting, the 7G-TRONIC is a wise choice. Steering wheel-mounted gearshift buttons are also offered.

Let's talk figures. The ML350 will get to 60mph from rest in just 8.1 seconds and only let up when 134mph is showing on the clocks. A combined fuel consumption figure of 24.6mpg may well be this car's Achilles heel although if you can afford to fuel it, you'll no doubt be grateful for the massive 95-litre fuel tank that allows a serious cruising Range between pitstops. With 272bhp on tap, the ML350 is rarely lacking in go and the 350Nm of torque on hand gives it decent overtaking ability. Granted, it's not the 510Nm available in the ML320CDI, but it's enough to be getting on with.

Quality is an issue that has plagued M-Class models in the past, but the latest cars are far tighter in this regard. Much of this has come from a change in factories. Whereas the quality control of the initial batch of cars produced from the Tuscaloosa plant in Alabama were rather patchy, latter models from the Austrian facility at Graz were a whole lot better screwed together. Some of the interior materials were a little half hearted but a nicely specified M-Class was, until the introduction of the Land Rover Discovery 3, still probably the best looking of all the big 4x4s. The lines have worn so well that the current generation M opts for an evolutionary look, keeping the same sporty stance and raked forward C-pillar but adding more pronounced wheelarches and a rising swage line along its flanks that may look a little too Toyota RAV4 for more conservative tastes. It marks a definite swing towards the sports end of the sports utility market and differentiates the Mercedes nicely from cars like the Land Rover Discovery and the Volkswagen Touareg. The next X5 will have its work cut out to offer styling quite as slick as the M-Class.

Although the sharply raked back windscreen and contoured body panelling give the M-Class a sporty, compact appearance, the tape measure shows just how artful its stylists have been. It's 150mm longer than its predecessor, 71mm wider and the wheelbase has grown by 95mm. It is also 7mm lower. Aerodynamics have been improved from a CD value of 0.39 to 0.34 with fuel economy savings of as much as ten per cent.

Both the front and rear suspension has been thoroughly revised for this generation M-Class, with a double wishbone front and a multi-link rear arRangement. For those that really want the ultimate in ride quality, Mercedes also offers an Airmatic air suspension system option that teams up with an Adaptive Damping System that adjusts the responses of the shock absorbers According to the situation in hand. There's also an optional off-road biased air suspension option which adds a two-speed transfer case with an off-road ratio, manually or automatically selectable diff locks and a version of Airmatic which raises ground clearance by 110mm to as much as 291mm. This means that the M-Class will now ford water up to two feet deep.

At 880mm, the distance between the front and rear seats is a full 15mm greater than in the old car, achieving a level more akin to a luxury saloon. Despite the additional rear legroom, luggage space goes up. Fold the 63:37 rear bench flat and there's 2050 litres (up by 30l) available. Removable cushions can be ordered as an option, which means that an entirely flat load floor can be attained, stretching 210cm to the back of the vehicle.

Customers will need to keep an eye on the bottom line and not specify the ML350 with too many tempting options. If they can manage this, they'll have a fine luxury 4x4. Not as good as its ML320 CDI sibling, but a good car nevertheless. Comparisons can occasionally be odious.