This past September, I picked up the 2001 ML320 and in October the 2001 MDX. In finding out what MB changed in their 2002 models, I've been kicking myself for not waiting a couple months and getting the 2002 instead. They now have standard fog lights, climate control, 17" wheels, more thought-out ergonomics, etc. But you know, more than I regret not waiting for the 2002 ML, I regret not getting two MDX's a lot more. The ML is a fine vehicle but in having the MDX, I have to say that I treat the ML like a "red-headed stepchild." (I hope that term isn't too offensive and if I offended anyone, my wrong/bad.)
My parents have an ML320 too and in all honesty, I think it is a more appropriate vehicle for them than the MDX... I just can't see them in the MDX because I guess it does look more "sporty".

By the way, they love taking the MDX out whenever they get the chance... (Question: How do you tell your parents "no, you can't have the car Saturday night?")
I guess just as there are a variety of people, there are a variety of cars. On paper, there are some things that the ML will outperform the MDX in but IMO, most people (myself included) don't push their cars to the limit where those numbers/stats really make a difference.
Take for instance, the wheel base size. The ML is a little longer but "who cares?" Rear side airbags? Good to have but often people make such a stong point out of this as if this alone should be the basis of a $40k decision. Another example is that, in real life, how often do you go up a mountain and have a Sparklette's Water Truck weave in front of you and have about a dozen or so 5 gallon water bottles fall off the truck and create an instantaneous obstacle course? If that did happen, I would scream a little and wet my pants a little and maybe after I collect myself and put my hair down, I might think, "I wish I had traction control." (Sorry, I got carried away... I just saw that happen in an Lexus RX commercial.) My point is that for the typical driver like me, the MDX is more than enough SUV for me. Yes, there are things that the ML has that the MDX doesn't but personally, the list is longer if you look at the other way around.
My opinion, recommendation, bias is toward the MDX. The reason for this is mostly based on everyday driving
convenience; yes the MDX is much-much more satisfying and pleasurable. If I based my decision on hypothetical situations where worse comes to worse, perhaps my chances might be a little better in the ML but then, how do you compare situations with so many "if's" factors?
*Optional 3rd row seating/cargo space question. I was wondering if the ML has changed the seat structure on the 2002. As I recall, when not using the 3rd row seats, they take a lot of cargo room and a little bit of origami training to fold away. And also, did they flatten out the panels that are attached to the back of the rear seats so that the cargo space is more usable in the 2002?