At this moment in time the Asus seems to be the fastest PocketPC out there.

http://pocketmatrix.com/reviews/a620/index2.php

You do realise that if you buy one of these then 3 months later a 600 mhz PPC might come out and so on and so on !

I've got an Ipaq 3970, got Spectrum/C64/MegaMameCE/PC Engine/NES/Master System/Doom/Gameboy/MSX emulators on it and they work very well. Some MegaMame games are slow, also SNES and Genesis games run too slow at the moment but like i say in the near future all these games will run fine