I guess it depends on how you intend to use the car. The G is a $20,000 premium over the ML. I can understand your wifes desire for some justification of the extra dough. As an urban commuter the ML is going to be the better of the two. It turns tighter, accelerates more quickly and drives much more like a car. For 99% of people the ML makes more sense. The Gwagen is a dinasour by comparison. Instead of the fully independant suspension it has solid axles. The G is very heavy and very boxy, not modern attributes. For off road use the G is the best, I don't care what the Hummer,Rover,Jeep people say. I have met them on the trail, lets face it, if they know they are jealous. On road the G may lag behind the ML a bit. The G500 is awfully quick for a truck that heavy. My experience is that they are plenty powerful for any task. I find that my G is very satisfying on road. It is soooo stout! Over the worst pavement the body structure barely drums, and it is a deep solid sound. The G is still hand built, I mean really hand built. They still bend brake lines by hand over a jig. Or you can buy something crafted by the UAW in Alabama or where ever it is. Interior space in the G is great, narrower than the ML but taller. Biased??? noooo , I just do not see any comparison, other than they both wear the star. I have had a BMW X5 as a loaner car for a while now and have driven it back to back with my G. I don't like the car/truck idea. They are bad cars, too tall and heavy, making them slow and poor handling. They are worthless off-road, which is important to me. That class, ML, X5, RX300 just baffles me. I like the G for its versitility and robust construction. It is also very uniquely styled in this day of egg shapes. I better quit rambling, my vote is for the G. Get out and explore a little off-road and your wife wont ever want an ML again.

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1995 G320
1984 280GE
1971 Unimog 416