We like
High specification, driving dynamics, impressive four-cylinder and effortless V6 diesel engines, high-tech driver aids

Room for improvement
Uncomfortable front seats, occasionally knobbly ride, piano black trim in ML350 BlueTec

A FOUR-CYLINDER diesel engine that can hustle a 2150kg SUV along and tow a braked trailer of up to 3000kg is impressive enough.

When an official combined fuel consumption figure of 6.4 litres per 100 kilometres is thrown into the mix – better than or equal to petrol small cars like the Toyota Corolla and Holden Cruze – then eyebrows certainly get raised.

There are also generous levels of standard equipment – including standard sat-nav, self-parking and comprehensive multimedia and safety kit – while both four- and six-cylinder diesel variants plus the soon-to-arrive, bahnstorming ML63 AMG are fitted with fuel-saving idle-stop systems.

The $81,400 starting price also undercuts similar-sized alternatives while bringing it within reach of buyers considering a product from the next size down, so from the perspective of purchase and running costs, Mercedes-Benz could well have a hit on its hands.

It would all fall apart if the driving experience was a let-down but we were impressed by the smooth new ML250 BlueTec.

Surprisingly flat cornering, decent levels of grip and direct, well-weighted steering all added up to a satisfying drive along the Great Ocean Road, while the lofty driving position provided excellent views of the scenery – and, of course, the road ahead.

Obviously the cost of such dynamics is a firm ride that transmitted some of the Great Ocean Road’s less than perfect surfaces into the cabin. We also experienced some bump-steer, but overall it was no worse than the average firmly-sprung German sedan.

Ride and handling is still not up to the high standard set by the BMW X5, but we found appeal in the M’s less macho, imperious feel than its Bavarian rival – something we feel is also reflected in the sleeker, less aggressive styling of the new M-Class.

It hides its bulk well and we found the M-Class easy to manoeuvre at urban speeds, helped by good forward and side visibility, a reversing camera and steering that becomes light enough for effortless wheel-twirling round town and when parking.

The M-Class also scores well for general refinement and even coarse-chip road surfaces resulted in a subdued rumble rather than raucous noise, adding up to almost no sensation of speed – meaning regular glances at the speedo are required if cruise control is not engaged.

The engine provided enough poke to feel the all-wheel-drive system shuffling power in its search for traction when accelerating hard uphill out of a rain-soaked hairpin and only really made itself heard in such scenarios.

A distant, distinctly diesel din emanated from under the bonnet when we applied pedal to metal, but it was well suppressed, vibration all but absent and the unit settled down to become inaudible at a cruise.

Compared with its six-cylinder ML300 CDI predecessor, the ML250’s 150kW/500Nm four-cylinder has peaky power, and torque outputs mean acceleration from rest to 100km/h is seven-tenths of a second slower at 9.0s – but this is the only statistic that compares unfavourably.

It would take a pretty special four-cylinder to match the effortlessness of the 190kW/620Nm diesel V6 fitted to the $99,000 ML350 – which is so smooth it could be mistaken for a petrol and is whisper-quiet apart from a whoosh under acceleration – but, believe us, the four-pot is a top effort.

During a stint of hard driving along the Great Ocean Road, we recorded average fuel consumption of 8.2L/100km from the ML250, higher than the claimed combined figure, but still inspiring considering how hard the little mill has to work against physics.

On mainly motorway driving with cruise control activated, the ML350 returned 7.6L/100km, only 0.3L/100km higher than its claimed average and low enough to require infrequent trips to the forecourt.

Less impressive was the seven-speed automatic transmission that, compared with the lightning-fast and silky-smooth eight-speed units employed by Audi and BMW, came across as slow-witted and clunky during spirited driving, even when using the standard paddle-shifters.

We were also disappointed by the distinctly un-luxurious front seats, on which we felt perched and somehow forced forward by the position of the backrest no matter how much we played with the driving position.

For us, the seats spoiled an otherwise pleasantly laid-out and attractive interior, which offers plenty of space front and rear. Perhaps drivers shorter than your 186cm-tall correspondent will find the seats more comfortable.

For those not used to driving a Mercedes-Benz product, basic controls can seem a little unintuitive at first.

The indicators and wipers are located on a single stalk, with the gear selector where the wipers usually are and the electric parking brake switch located low on the dash, by the right knee.

As with many cars, the cruise control stalk is situated below the indicator stalk, but operating it in the M-Class while driving requires familiarity as the labels are obscured by the steering wheel.

It soon becomes second nature, though, and we grew to like the combined indicator and wiper switch, especially the satisfying action – common across most of the M’s switchgear – that presented a quality, built-to-last feel.

A good-to-grasp steering wheel presented intuitive audio and telephone controls that also enabled easy interaction with the useful multi-function display between the dials, which provides fuel-use monitors, digital speed readout (more useful than the closely-stacked analogue speedo), maintenance information and driver aid setup or information.

Combined with shortcut buttons for the main central colour screen, we found the rotary controller for the latest COMAND APS infotainment system pleasant to touch and easy to use.

Clear graphics and sat-nav mapping, good-quality sound and easy Bluetooth integration made the system a pleasure to use, while the knobs and buttons for the dual-zone climate-control were similarly simple and intuitive.

Although the ML250 loses the 350’s leather-look stitched upholstery for the dash, classy soft-touch coverings are used and complemented by swathes of attractive brushed metal trim.

In contrast, we were unimpressed by the piano-black trim of the ML350, which has a glossy finish that causes distracting reflections for the driver while the faint wood-grain visible through the lacquer makes it look as though it is dusty and covered in fingerprints.

A driver fatigue detection system is standard across the range, and we enjoyed the full complement of driver aids fitted as standard to the ML350 and optional on the 250, headlined by adaptive cruise control, lane-keeping assistance and blind-spot monitoring.

These three systems make for effortless motorway cruising. The car maintains a pre-set distance behind the vehicle in front, illuminated triangles in the door mirrors warn of a vehicle in the blind spot and the steering wheel gently vibrates when changing lanes without indicating or gently pulls the car back into lane if it detects the driver drifting across a solid white line.

One concern we have about all these driver aids is the temptation to disengage from driving completely and we found ourselves more willing than usual to mess around with the car’s various on-board infotainment systems on the boring stretch of motorway between Melbourne and Geelong.

A generous glove compartment, space beneath the central front armrest, smallish door bins, a coin tray, cubby under the centre stack, sunglasses holder, a net in the passenger footwell and small area by the cupholders (located under a roller door) were among the numerous storage areas for front occupants, but the M-Class caters less well for rear passengers.

The cavernous 690-litre boot expands to 2010 litres with all the seats folded down and looks as though it could accommodate a small third row of seats like the X5. However, Benz customers wanting to carry more passengers only have the SUV/people-mover crossover R-Class or vastly more expensive and huge GL-Class models to choose from, unless they go the van-based Vito/Viano route.

As customers head to smaller, more efficient, less expensive luxury SUVs – something Mercedes-Benz does not offer in Australia due to the absence of a right-hand-drive GLK – and the age and dwindling supply of the previous M-Class, the company has some catching up to do.

If anything, the new M-Class – and especially the ML250 – puts it back in the game, providing a compelling purchase and running-cost equation, even if rivals are already returning fire with price reductions and added value.

Mercedes expects its diesel duo to account for 80 per cent of sales once it has a full range. The petrol V6 and V8 models – including the beastly ML63 AMG – arrive in the next few months with range-wide average fuel consumption improvements of 25 per cent.

With the arrival of the new M-Class, the BMW X5 is now that bit harder to justify as the default luxury SUV choice.

The Benz also trumps ageing competitors like the Audi Q7 and Lexus RX while presenting a tempting proposition against top-spec variants of impressive non-premium alternatives such as the Volkswagen Touareg and Jeep Grand Cherokee, or even smaller products like the BMW X3 and Audi Q5.