LARGE SUVs are often criticised for failing to keep the off-road promises that their jacked-up ride-heights, chunky bodywork and fat tyres make, particularly when it comes to the more luxurious end of the segment.

One model that has not entirely escaped animosity is Mercedes’ ML-Class, but at the launch of the now renamed GLE, the German car-maker gave us an opportunity to pitch its new SUV range against some of the most unforgiving terrain Austria’s Alps have to offer.

For now, all versions of the GLE offered in Australia will be offered with Mercedes' 4Matic four-wheel drive system sending torque from the range of petrol and diesel engines to all corners, but Mercedes offers a package for owners wanting to challenge the commonly held opinion that the GLE is more soft-roader than off-roader.

Pricing is yet to be announced for the extra Off Road equipment pack but when fitted to the previous ML-Class the bottom line was increased by about $10,000 and the price of the kit for the new GLE is not expected to move by much.

For your money, the optional kit adds a low-range transmission, a further 50mm of height to the variable Airmatic suspension, more selections in the Dynamic Drive switchable handling settings and additional vehicle information displayed in the dash-mounted screen. Our test vehicles also had a set of top-quality General Grabber AT tyres fitted.

Setting out on the trail took us and the GLE400, priced from $109,900 Down Under, into spectacular Austrian mountains and along single-lane tracks that quickly steepened. In low range, the knobbly tyres bit into the loose rocks and gravel and did not seem phased by even tricky manoeuvres such as tight hairpin turns while climbing.

The 4Matic system does a great job selecting which tyre has the most grip available and pulling away from a standstill on very steep gradient, and damp mud could not halt the big Merc.

Descents were also dealt with in the same sure-footed manner using the hill-descent function. Unlike some some similar systems, the Mercedes solution allows the driver to set the rate of descent using the cruise control and we managed to confidently negotiate a dizzying 60-degree forward tilt.

Approaches to steep declines are made significantly more simple by the nose-mounted camera which shows the way ahead when the bonnet obscures a drop.

The 360-degree view normally used to aid parking also gives a useful view of surroundings when off-road and is constantly displayed in the screen.

Rather than wade a small lake in the trail we decided to skirt around the edge which challenged the GLE with both boggy shores and a 26-degree tilt angle as one side of the vehicle rode the bank while the other tiptoed in the water.

Our instructor told us we needn’t worry about the extreme angle until the information monitor read closer to 35 degrees. The display can also show steering angle and other useful vehicle information when tackling the road less traveled.

Finally we concluded our trek into the mountains via a deliberately constructed series of bomb-holes and obstacles designed to leave one wheel in mid-air and demonstrated how the 4Matic system locks a wheel with zero traction. Once again, progress could not be interrupted.

After parking up the toughened GLE400 we hopped aboard the entry-level $86,900 GLE250d of a brief trip along some surfaced Alpine roads to experience the 2.1-litre four-cylinder diesel and decent levels of standard equipment.

Like all the other GLE and GLE Coupe variants we had sampled so far, the base diesel engine offers a very good option combining adequate performance – actually surprising given the GLE’s size – and an indicated fuel consumption of 7.3 litres per 100 kilometres.

Its interior is well appointed with all the quality you find in higher-spec variants. The dash has all the right switches and functions but the layout is perhaps not up to the style and design of the rest of the GLE features.

Handling is surprisingly lively for a model not selling itself on the same sporty credentials of its higher-performing siblings but the boggy brake pedal that all but the AMG63 S are guilty of is a little distracting.

We like the gutsy diesel’s 150kW/500Nm performance, but as is the case in other Mercedes models sharing the same engine, it can sound a little agricultural and not as refined as some other three-point power plants.

For an entry-level option the base diesel is a very attractive proposition with great all-round features, appealing styling and great day-to-day usability.

Finally we had a brief chance to sample perhaps the most significant change to the large Mercedes SUV line-up – the GLE500e plug-in hybrid.

Throwing a bag in the boot of the plug-in hybrid revealed the notable boot space penalty which is reduced by 130 litres thanks to the battery, which resides under the luggage-area floor. The space is still versatile with folding rear seats to boost the capacity if necessary.

On a full charge and in pure electric drive, the 500e can travel about 26km and on flat roads we were exceeding that figure by a notable margin, but a slight incline soon had that range plummeting. Before the battery was completely exhausted we engaged hybrid mode and the 3.0-litre petrol engine helps out while recharging the battery.

When asked to work together, the electric and petrol motors lend impressive performance to Mercedes’ first PHEV SUV with sitting linear acceleration and the milestone 100km/h coming up in just 5.3 seconds.

Unlike some other hybrids, the Mercedes’ regenerative braking has not resulted in a spongy brake pedal and the GLE500e drives in a very similar way to the rest of the range with only the occasional silent cruising to give the game away.

Owners will also be pleasantly reminded of its hybrid system every time they fill up, with our short drive using just 5.0-litres of fuel every 100km.

The delicious quilted white leather interior and contrasting black synthetic suede roof lining added to the sense of quality for those who don’t mind dipping into the extras list.

With five GLE choices coming to Australia later this year, including the vicious AMG and a choice of two other petrol and diesel variants, the ML-Class replacement will offer something for everyone in the market for a large SUV.

Mercedes-Benz GLE pricing*

250d (a)	$86,900
350d (a)	$104,900
400 (a)	$109,900
500 (a)	$127,900
AMG 63 S (a)	$189,900