I had a new 96 Jimmy, but I believe its about the same as a 99. The only real complaints that I had were regarding comfort. I could never find a comfortable spot with the driver's side power seat. The shape and contour of the seat itself was part of the problem, it didn't quite match the shape and contour of my big butt.
The third and most serious comfort problem was that when it was cold outside, a freezing cold draft would blow up through the firewall around the steering column. It was bad enough that my wife had a real hard time driving it when it got cold. The dealer tried everything to stop the draft, but finally gave up. We traded it off after 2 years.