Considering the only games in English it really has to compete with are the hand crippling Guitar Hero series or obscure midi-instrumental underground cult favorites like Music Mon-stars, I'd say it's pretty good. Not sure if I'll keep it for very long if only because I've played all these songs in the 360 version already, but the basic concept is cool:
You play all 4 musicians at once. Start on guitars and when you hit a certain amount of points in a row, the notes turn clear, giving you a few seconds to switch to another instrument. The goal is to keep switching and maintaining as much of a high score as possible using all 4 instruments.
It would be great if we get a sequel after the Holidays featuring some new songs or songs featured as DLC in the console versions without the Lego gimmick. The engine is already in place and it's definitely a more fulfilling design style than any of the DS Guitar Heroes have been.