I have 4 N90s bodies that get used a lot for either field work or underwater photography (yes I use a housing). I also have a F5 that is a wonderful camera but for the most part my N90s's will do everything I want and more.
The added bonus is that is one gets broken I just chuck it and buy another as they are so cheap. The N90s is also lighter and smaller than the F5 unless I put one of the battery grips on it. If I feel I need the extra juice that's when I pull out the F5.