I have a plain prism F and F3 and like both. My F is beat up pretty bad - shutter button position never bothered me on the F. The film advance lever on the F3 is very very nice though - nothing better from nikon if you ask me.
I like the idea of the F being totally mechanical....but film advance feels like there is a hump about 2/3's the way through, and the lever itself feels very thin somehow. Every time I advance the film on the F it sorta feels like the lever could snap. And the F is bottom load on the film, sort of a pain if you go through film fast and are used to a film door. Another thing, the viewfinder on the F is somehow nicer than the F3 to me. Seems bigger or brighter.