It would be awesome if it finally had a fully functional Dreamcast emulator. They demo'd it almost 2 years ago and I haven't heard about any progress since.
Other than that it's mainly a bunch of homebrew, linux open-source ports of PC games engines(ex. Tyrian, Freeciv, Free Heroes, etc.), and emulators.
I would be very hard pressed to purchase something like like this for $500 when my PSP performs the majority of it's functions already minus the keyboard. Although with my PSP-1000 I could technically use a iR keyboard with certain hombrew programs.