I have 2 x F80's and they are both light and responsive. I have no problem with the viewfinder although I wear glasses and use them in preference to my other Nikon a F801s. They are quieter with focussing (No high pitched whine) and the metering is absolutely spot on. The only reason I keep the F801 is the F80 cannot take Infra red film, as a IR led is used to gauge where the film advances to.
The batteries are lithium and not the AA cells which means I always have to keep a couple of sets as spares, but saying that they seem to last a very long time providing that you do not use the flash frequently. Talking of which if I use a separate flash on the F801, with a SB28 it will remain on the widest setting, whilst the F80 will zoom in and out as the focal length is changed.
If I am away on the bike I always take one of the F80's because the lightness makes it easier to deal with when riding