Q really is a great emulator based on QEmu. The UI is very nice and friendly. ArosMAX is sweet on it. (The included DOOM runs plenty fast enough to be played.) I mess around with Windows 98SE on it as well just to compare how well AROS runs against it on the "same hardware". I also use it to test out the latest releases of ReactOS (Windows clone) which is also coming along nicely.
I have not been able to get anything PowerPC to boot on it though... (My YellowDog disc as well as my OS X Tiger installer doesn't do anything.)
Check it out though if you have a Mac... better than supporting MS by buying VirtualPC.
