Toyotas and Nissans lead in the popularity stakes, BMW and Land Rover are strong where "Sports" is more important than "Utility Vehicle", and American-built vehicles offer an awful lot of metal for your money these days.
All of which leaves Mercedes with the dual problem of making their range more appealing to the traditional buyers of their competitors' vehicles, while trying to convince their own loyal customers that a Mercedes 4x4 is the real deal in terms of off-road performance.
To achieve the former, current models will soon be available in "Grand Edition" trim, with a host of external cosmetic enhancements, plus cabin equipment upgrades. No doubt features such as 20in wheels, body coloured diffusers, panoramic sunroofs and keyless entry will help Mercedes sell more 4x4s, but they're unlikely to help improve off-road traction in Liwa or the hills of Hatta.
So in order to prove just how capable their vehicles are over rough terrain, I was invited out to lunch on consecutive days by Mercedes, and offered a choice of the GLK, ML, GL and G-Wagen models to make the journey there and back.
"So what?" I hear you ask, "A fancy lunch date doesn't prove anything" but on both days, the route to the restaurant involved traversing a Jordanian mountain range. And after scrabbling for hours up 1,700-foot climbs on 80 per cent slopes made of loose shale, along tracks consisting of seemingly endless boulder-filled ruts, through some spectacular wadis and across numerous wheel lifting ridges, I think it's fair to say that the entire vehicle range showed itself to be suitable for the task — with one in particular proving to be as agile as a mountain goat.
The GLK is the most recent addition to the Mercedes SUV line-up and also its smallest. Powered by either a 231 or 272bhp engine, it is the only one of the four models not fitted with manually selectable locking differentials.
Since it also has the lowest ground clearance of the range, I was expecting it to struggle with the rough off-road conditions, but except for a couple of instances when particularly deep ruts proved difficult for the independent front suspension, it coped well.
Traction control is maintained thanks to the off-road function of the ABS system, which senses that one wheel is spinning and so transfers more power to the other side of the vehicle. It's not a diff lock, but provided the electronics always work, it's the next best thing.
A couple of other notable features fitted throughout the range are the Hill Start Assist and Downhill Speed Regulation. The former senses that the vehicle is on a slope and maintains pressure on the brakes for up to three seconds after the brake pedal is released, so there's no danger of the vehicle rolling backwards, while the latter allows the driver to set and control the descent speed without any input on the throttle.
On the one hand, I can appreciate that these functions make off-road driving safer for the inexperienced driver, but on the other, having learned to drive in old-fashioned mechanical 4x4s myself, I do feel that part of the challenge of off-roading is safely mastering control of the vehicle. Doubtless, Mercedes-Benz knows its target market, and by putting safety first and eliminating the possibility of losing control on a steep slope, they'll attract more customers who want the thrill of off-roading, but not the risk.
Heading down the mountain but up the product range, I next sat behind the wheel of the ML350 fitted with the optional Off Road Pro Technology Package. Now, I've seen silver painted plastic bash guards and colour matched wheel covers described as off-road equipment by some manufacturers, but the Mercedes package is the real deal. The height adjustable air suspension, low range gearing and rear axle and centre diff locks are genuinely desirable features on an off-roader, and the ML350 hopped, skipped and bumped its way down the mountain with confidence.
What also caught my attention was that the interior of the ML was definitely a more Mercedes-like place than earlier models I'd driven. It seemed far better trimmed and fitted, a fact which will not go unnoticed by consumers ready to spend more than Dh200,000 in the luxury SUV market. Across the whole range, there is a sense of commonality of controls, function and design which made switching between vehicles a breeze, and which other manufacturers might do well to implement. Of course, that also means that if something annoys you in one model, it'll annoy you in all of them.
I wonder why Mercedes has fitted a non standard MP3 connection in the centre cubby box, then decided to charge extra for the interconnecting cable. Is it to ensure that if Apple changes the classic iPod connector design in seven years time, you'll still be able to use one in your Mercedes? Or is it so they can charge more for the cable in the meantime? Who knows?
Next on my list of mountain climbing motors was the G-Wagen, another vehicle which seems to have benefitted from some close attention from Mercedes-Benz's quality assurance department. I last drove one two years ago and at the time, I commented about a vibrating bonnet which was a constant distraction, and interior trim which left a lot to be desired. But just like the ML, sitting inside the 2010 G-Wagen seemed like a completely different — and better — place to be. And with central, front and rear locking differentials, a 5.4-litre V8 engine producing 530Nm of torque at 2,800rpm, beam axles front and rear, plus short body overhangs and no superfluous trim, it took less than ten minutes for the G-Wagen to establish itself as the car I most enjoyed on this off-roading excursion.
We're back to the ‘old-fashioned mechanical' argument again and while the GLK, ML and GL are modern iterations of an old theme, with car-like suspensions and controls cleverly adapted to go off-road, the G-Wagen benefits from being an older, classic 4x4 design, onto which selected benefits of modern technology have been grafted.
When you combine a seven speed gearbox with that much torque, lock the differentials and let the electronic traction system lend a helping hand every now and then, the G-Wagen sets off up mountain passes faster than an overrated Portuguese striker reaches for his hair gel and mirror. The fact that you can enjoy such off-roading excellence in comfort and style means the G-Wagen is likely to remain in (limited) production for years to come.
My strongest praise for the capabilities of the electronics and gizmos on board these vehicles actually comes from the time I spent as a passenger, not the driver, in the ML. I was accompanied for the two days by the charming Sabine who, despite having grown up surrounded by mountains in Austria, had very limited 4x4 driving experience on sand and none on rocky terrain. During the first day, I drove for much of the time and Sabine was happy to watch and learn, particularly on the more daunting sections, but when we were handed the keys to the ML, I suggested she might like to spend some time behind the wheel. A little over-cautious at first, which is fine when you are tackling mountain passes with "fresh air corners" as our instructor Duncan delighted in calling them — within 30 minutes Sabine had transformed into a confident and capable off-roader. Concentrating on picking the right lines through the rocks, she relaxed knowing that the ML's locked differentials and electronic trickery were taking care of the rest. After an hour, I was hopping in and out of the vehicle to grab photos of the climb and Sabine was quite happy to drop back or press on ahead with the group without any instruction. And while much of the credit must indeed go to her, the fact is that the safety and traction control systems on these latest Mercedes instilled the confidence she needed to pick up the art as quickly as she did.
Unfortunately, time restraints meant that I was unable to venture cross country in the GL 450, but during a two hour drive on both twisting and fast tarmac sections, the power of the 4.6-litre V8 engine was abundantly clear. Yes, it's a big heavy car but it never feels like one. The 4ETS traction system, independent air suspension and adaptive damping combine to make for a relaxing drive. In fact the only thing missing was a selection of favourite tunes from my iPod…