It does perfect emulation of NeoGeo, Snes, NES, Genesis, Turbografix16/PCengine (including CD games). It does portables like Game Gear, Atari Lynx, and Bame Boy/Game Boy Color. It does classics like Colleco, old Atari systems, and Amiga. It does an absolutely perfect Capcom CPS2 (marvel v capcom, street fighter series, etc). It does an older version of Mame (.34, still tons of good games). It does older PC games like Doom 1 and 2, Quake, Wolf3d, commander keen, Duke Nukem 3d, Flashback. It does many of the old LucasArts games like Day of the Tentacle, Sam & Max, Escape from Monkey Island. It also has some good homebrew games.
Works in progress include Game Boy Advance and PSX, which have a few playable games but need more work. I'm confident that it will eventually play many games at full speed from those systems, but probably not all of them.
It also plays DivX and Xvid movies, and MP3s, and handles text files and pictures.
Yes, I love it, as you can tell.