They look really cool, they'll play all Gameboy and Gameboy Color games, as well as new games, and they're relatively inexpensive, all things considered, at $99. (As I recall, that's the price the original Gameboy went for).
Especially since they've released some of their cool older games for Gameboy Color, if they continue doing that. . . I would love if they released Final Fantasy 1 for Gameboy Advance, or some of the other games I used to love.