A buddy of mine has one here, one in Africa, and he loves them.
But, unless you're gonna cross the Namib desert they're probably a bit OTT.
They are feckin tough, real off-roaders and you select the diff lock not some computer over which you have no control.
However, all the drawbacks mentioned above are true, low mpg, eye-wateringly expensive parts, most MB dealerships can't/won't service it..........
Mind you, if it's what you want and you can afford it...................go for it, you'll probably love it.