Bought the ML after testdriving X5, Lexus 470, LR4, and QX56..were actually on way to buy QX when we decided to just look at the ML. Test drove the 350 and took it home to see how it would accommodate our family roadtrip needs..perfect. When we ordered, only the 350 was available but was able to upgrade to the 550 a day later. It's awesome..a real sleeper. Steering not nearly as precise as the X5 but better than the QX. The safety features by far exceed any of the other SUVs we tested. Exterior not very sexy..would prefer a Cayenne or X5 or even the QX but for a family tourer with performance the ML550 is hard to beat! And we get 19.5 mpg average.
Performance and interior capacity. Also like the Bluetooth audio streaming. Most importantly we like the safety features, i.e. distronic and lane assist.
If all the MLs looked like the ML63 I'd be happy but not all owners would agree..for sure not the ones who pay $96K.