We have owned a 1999 Mercedes-Benz ML430 vehicle for four years. It has been extremely reliable. This is our second Mercedes and won't be our last. I recommend keeping up on service. We have had no problems. I do wish the front leg room was just a little bit bigger. I am 6'1" and it could be just a little longer.
It handles well and is fun to drive.
The cup holders need improvement. Also, the CD deck is inconveniently located in the back hatch area.