WinUAE is nice and all but I would never replace my A1 with AOS 4 to a PC with WinUAE. I've tried WinUAE on a PIV 2.4GHz and an AMD 2700+ and yes it was fast but not even close to how it feels using a real Amiga and limited to AOS 3.9.
I'd say that goes for most things. Which is better, a classic car kit or a real classic car?
Nothing beats the real thing, accept no immiations.