Well you may disagree, but I have heard alot of people who prefer the AF speed on the F80 over the F5..
I have no comparable experience with the F5 but in general AF speed depends on the lenses too. Speaking about my own experience Maxxum 5 and 7 do have a better AF speed !
Now to render one of my personal opinions, the F80 is one of the worst ergonomically balanced cameras I have ever held in my hands..
Depends bit on the mounted lens too but I have no complaints at all.
This body is small and light and that's what I love. Plastic is no prob, I don't go to war with it.