After trying it out, I'd even dare say this is the best Guitar Hero game on the DS (from the technical side, not from the pretty meh playlist side). More instruments, sound quality is improved, you can create you entire band, drums play just fine (even without the drum skin)...
The only downside I've noticed so far is the vocal side. While it is great to take functionality of the DS microphone, I found the game to be pretty unresponsive unless your face is all up in the DS (or you scream from the top of your lungs
) which makes the lyrics and the little marker thing really hard to see.
Whoever liked previous On Tour games should love this one.