For the last few years, Jeep products wearing the Grand Cherokee badge have been a source of aching disappointment to me. I have wanted to like them, but not one has been as appealing as the original model of the mid-1990s. You can imagine, then, my trepidation as I approached the new-for-2011 model, and perhaps also my delight when I discovered that it blows all previous Grand Cherokees out of the water.It doesn't hurt that this one shares a platform with the next-generation Mercedes-Benz ML-Class, and is larger, lighter and stiffer than its predecessor. Ironically, the older car's three-litre Mercedes diesel engine has been ditched and replaced by a more powerful one built by VM Motori and co-developed with Jeep's new owner, Fiat.There have been VM-powered Jeeps before, and they have been resolutely awful. This one is something of a wonder. It's powerful enough to give the Grand Cherokee a 0-62mph time of 8.2 seconds, yet combined fuel consumption on the EU test cycle is 34.0mpg (which, according to the trip computer, is about what you'll achieve on a gentle open-road cruise).Furthermore, whereas previous VM engines have given me the impression that I was sitting within ten feet of a machine gun, this one is almost whisperingly quiet. I wasn't expecting that.Nor was I expecting the Grand Cherokee to ride well. For the last ten years or so, none of them have, but this one is extraordinarily smooth, not just for a large SUV but for almost any kind of car. The 20" wheels and their 50-section tyres add a measure of jiggle to the process, but they're fitted as standard only to the range-topping Overland reviewed here, so you don't have to have them if you don't want them.There is, however, not much to be done about the steering, which - even for a vehicle of this type - is rather vague, despite Jeep's claim that the Mercedes platform makes it more precise. The turning circle, though, is amazingly tight.The driver's seat has a very wide range of adjustment, particularly for height, and there's enough room for tall rear passengers if the seat is pushed back. It can be pushed forward to increase the cargo volume, but the luggage cover doesn't move forward with it, so in this case some of your chattels are going to be exposed to prying eyes. The boot floor is quite high, but since this is partly to leave room for a proper spare wheel rather than one of those space saver pieces of nonsense (or, worse, a tyre repair kit) I'm not going to complain about it.If you want even more luggage space you can, of course, fold down either part of the split-folding rear seat - a simple manoeuvre which involves nothing more than one pull of a lever on each side of the car.You'll have gathered by now that this is, to me, the best Grand Cherokee in years, but there are some peculiarities. There is no resting place for the driver's left foot, the rear three-quarter visibility is dreadful, and for some reason the engine won't switch off unless the automatic transmission is in Park. If this is a safety feature, it's one of the strangest I have ever come across.There are just two trim levels, and they're quite widely spaced. The Overland costs £7200 more than the more basic Limited, for which not inconsiderable sum you get a navigation system with a 6.5" touchscreen display and a 30GB hard drive, blind spot and rear cross path detection, forward collision warning, adaptive cruise control and Quadra-Lift air suspension, which has no fewer than five height settings (across a range of just over four inches) and is no doubt partly responsible for the excellent ride quality. Engine 2987cc, 6 cylinders Power 237bhp @6200 rpm Transmission 5 speed automatic Fuel/CO2 34.0mpg / 218g/km Acceleration 0-62mph: 8.2 seconds Top speed 126mph Price £43,995 Details correct at publication date