Just noticed the above site's file server is offline. The site is still there though so it's worth keeping the link here.
is another place to download the emulator. I've just checked it and it's fine.
Personally I think the emulator is pretty well executed considering the limitations of the controller compared an Amiga's mouse, joystick and keyboard input devices!
Everything I've tried runs full speed and sounds great but I've only tried A500 stuff. It runs off CDRW no problem so you don't have to copy to your xbox's HD if you don't want.
I like the screen sizing and positioning feature along with the opportunity to have everything anti-aliased but it really could do with an option to be able to change the buttons into joystick movements and not just keyboard key emulation. Pressing up on the D pad to jump in platform games just isn't natural!