Are you really comparing the Nox to a vehicle that costs more than twice as much? I agree that Mercedes makes some nice stuff, but as far as quality control/reliability they have been no better or even worse than the domestics in recent years. My sister has a fully loaded 05 E500 which is very nice...smooth ride, good handling/brakes and a powerful engine. Of course the thing has scared her enough that she always rents a car for out of town trips...the center stack and gauge electronics have freaked out twice, the rear climate control stopped working, the wipers stopped working, bits and pieces of interior trim (along with the flimsy cupholder) have fallen off/broken...and the piece de resistance was when the air suspension spectacularly collapsed when she was more than 200 miles from home. (and 200 miles from the nearest Mercedes dealership as well) YMMV and your ML350 may be rock solid until the day you sell/trade-in for something else...but just remember that you can't compare vehicles that are that far apart in price.
Also..if you can easily afford a decently equipped ML350...why did you only get a 1LT with the 4cyl?