The Pegasos Book (
http://thepegasosbook.wikipeg.org/) contains almost everything you need to know about Pegasos. So download and read it
I myself have Pegasos1. It is nice machine for Amiga users, but if you can afford, go Pegasos2 instead. Pegasos1 has some small things which don't work as well as on Peg2. Like little sound distortion when using 3D acceleration, picky for memory units, Linux distros and Mac-on-Linux is easier on Peg2, not so polished Forth support in OpenFirmware, slower than Peg2 (but still lightning fast compared to classic Amigas)... but if you can live with those and get Peg1 really cheaply, it's certainly is a nice computer. But as others said, it's not for old Amiga games, it's for Amiga apps
BTW, there is now 3D support for better gfx cards for Peg1 too. Radeon 7500 is really nice, but I'm not sure if it's the best anymore
