An all-new Mercedes-Benz M-Class is due in the UK later this year, but in the meantime the German carmaker is adding value to its prestige SUV range with the M-Class Special Edition.

We tested the mid-range ML350 which is powered by a 3.7-litre V6. In SE trim, it receives more than £4,400 of extras fitted as standard, including a host of AMG-model parts, for less than a £2,500 premium above the standard model.

Inside, the vehicle has gadgets and luxuries sales staff can utilise to draw prospective buyers’ attention away from the dark interior.

ABS with EBD and brake-assist, plus the M-Class’s advanced 4-ETS electronic traction system are standard. Such driver aids are welcome, as the M-Class’s very average on-road manners show it up when compared with the more proficient BMW X5. While happy to hustle along on straight A-roads at speed, show it a bend and it wallows, while slow steering further saps driver confidence.

The 3.5-litre V6 provides 255lb-ft of torque at 3,000-4,500rpm, making it a good tow-car.

One of the greatest threats to the current M-Class is the impending arrival of its second generation, unveiled at the Detroit Motor Show. This will have more efficient engines, a more sporting appearance, and yet more driver aids to help it master rough terrains.

Strengths:Capable, roomy, well equipped
Weaknesses: Gloomy cabin, poor economy, looking dated now
Opportunity: Extends the prestige appeal
Threat: Buyers will wait for the new model
USP: Better equipment and better value
Price: £36,330
Engine : 3,724cc V6, 235bhp
Transmission: 5spd auto, 4x4
Performance: 0-62mph 9.1sec; top speed 127mph
Efficiency: 22.2 mpg (combined); 305g/km CO2
CAP RV (3/30k): £15,425 (43%)
Rivals: BMW X5, Lexus RX300, Discovery3, Cayenne