Have a look at the Volvo equivalent. XC90 or something; has the seats, I believe, and it's been raved about by various credible reviewers.
The M-class Mercedes is, by all accounts, awful. I wouldn't be surprised if you could negotiate $10k off the price at a dealer, as this car is outclassed by practically all the opposition and MB knows it. If your heart's set on a Merc offroader, I'd suggest buy the very serious G-Wagen, or check the post entitled 'Oddity'
