There's no questioning the breadth of ability possessed by the Mercedes GL. It is excellent off road and respectable on it – particularly thanks to its two excellent engines, which give the buyer a choice of sheer polished performance, or real-world pace and decent economy.
If you regularly carry seven over long distances – or five and huge amounts of luggage – the GL-Class is something of an unsung hero. It's certainly a nice way to travel and seats seven with absolute ease. But you pay handsomely for the privilege.
In many ways, the GL falls into an odd gap in the luxury SUV market. Recent price rises for the flagship Range Rover mean the diesel GL is more of a competitor for the seven-seat Discovery, which is also a proper off-roader.
The GL 320 CDI costs marginally more than the most expensive Discovery HSE, but then it is arguably more of a luxury experience, slightly more spacious and probably better built.
It is a very small niche, but if you do want a very highly-speced (the GL350 lacks only leather trim), very spacious seven seater with genuine off-road potential, it is either this or a flagship Discovery. And the GL has the edge over the Land Rover in terms of luxury and build.