Any number of my friends were desperate to buy a copy of Guitar Hero: On Tour for the DS. Their lust for the game has been completely untempered by reason or practicality, even after it was mentioned that neither RedOctane nor Neversoft were in any way involved with the thing.
I haven't had a chance to play On Tour yet, but in the interests of possibly saving people some money and disappointment, you might want to check out the heavily negative reviews:
Gamespot: "Cumbersome controls and several other shortcomings make this guitar permanently out of tune." 6 out of 10.
IGN AU: "A compromised version of Guitar Hero that is really only an adequate first draft." 6.5 out of 10.
Gamesradar: "Tour cancelled due to broken wrists. [...] There's no sense of stardom, no wish fulfillment, just a series of colored notes that you have to hit." 6 out of 10.
Having been busily predicting that this wasn't going to be the portable sex-replacement that everyone seemed to be expecting, this comes as no particular surprise to me, and I don't intend to shell out money for the thing. However, if anyone who has any real experience with the console Guitar Hero games has played the DS version and wants to give a contrary opinion, please feel free.