Thank you all for your inputs !

At this very moment, I have the F100 and the F80 as auto-focus bodies. I was considering to go for the N90s as well but since the difference is more in terms of ergonomics, I'm gonna wait for a very good price before purchasing it.

Since I also have the FE2 and the FM2n, both in perfect condition, I think the F90s could wait while I am gonna take care of my GAS episode.