Infiniti M saloon

Drive

Only two engines are available: a 235bhp 3.0-litre diesel and a 315bhp 3.7-litre petrol. The former is smooth, refined and delivers plenty of mid-range punch. It can sprint from 0-62mph in a rapid 6.9 seconds. The petrol is marginally quicker from 0-62mph, in 6.2 seconds, making for easy overtaking. Both models use a seven-speed automatic gearbox, which can feel ponderous if you up the pace. Those seeking agile handling would be better served by opting for an S-spec model, which gets a tauter chassis and four-wheel steering system. In bends, the M offers decent grip and body roll is well controlled.

Comfort

GT models prioritise comfort, and soak up imperfections in the road well. Standard double glazing means wind noise is kept to a minimum, and while the diesel unit is audible at idle, it's not intrusive. The 20-inch wheels found on top-spec S cars make for jittery progress. Finding a comfortable driving position is easy, with plenty of seat and steering wheel adjustment. Shallow rear windscreen restricts visibility slightly.

Reliability

Infiniti has an impressive reliability record and offers first-class customer service, so any problems should be dealt with smoothly and efficiently. The M feels well built and the quality of materials used is superb, although it can't quite match premium German rivals.

Practicality

There's acres of room in the M's cabin, both front and rear, for four adults. Legroom is ample, and despite a swooping roofline, it doesn't impact on headroom. However, the intrusive central transmission tunnel means that the middle seat is for small children only. Petrol models boast a useful 450-litre boot, while diesels get a more generous 500-litre load area. Yet both are outclassed by the BMW 5-Series and Mercedes E-Class.

Value for money

Even the entry-level model, which costs £38,445, comes loaded with equipment, including keyless entry, reversing camera and dual-zone climate control. Range-topping S-spec cars add sports suspension, gearshift paddles and four-wheel steering. However, the M is expensive to buy and resale values aren't expected to compete with rivals. Its exclusivity on the UK market is a plus point, though.

Running costs

Although the introduction of a 3.0-litre V6 diesel engine to the range has improved fuel economy slightly, returns of less than 40mpg and CO2 emissions of 199g/km are still poor, and lag behind class leaders. The petrol's economy figure of 28mpg is truly abysmal. Not only are fuel costs high, so is annual road tax – the oil-burning M sits six tax bands above its BMW 5-Series equivalent. Servicing and parts are also pricey. At least the forthcoming hybrid should improve things in this category.