Just got my copy, listened to the soundtrack on the drive to campus. It's okay, fun to hear the MIDI versions, but I'd have much rather the full versions. The art book has some cute stuff in it, I really like the art that puts the characters in places like school, and normal worlds, etc. I'd buy a full book of this series artwork.
When I first saw the game I saw the cover of the art book and thought it was gonna be a Final Fantasy Tactics Advance like story, where average people get pulled into a fantasy world. Then I read about what the game was about and was bummed out.