Amithlon would be the first choice on supported hardware.
With accelareted gfx it's ways faster then Winuae on the same machine
The problem is to find fast supported hardware
Amithlon on a Virtuall machine is in general a bad idea...
with uae/winuae you have nearly all amiga models
while Amithlon is a 3.9 system with rtg only
there are no native screenmodes (ok i lied, on some programs it can be cheated to a rtg screen)
if you want to play games, better go with winuae