I got my hands on Guitar Hero On tour. I'd heard bad thing but I was hoping the niggles would be work around able, well not without a lot of work.
The first problem with it is the grip button thing it just slots into the DS's gameboy slot and it is very easy to dislodge if this happens mid game you have to reset the DS. It really needed to lock to the ds some how maybe a clip that held it onto the back of the device.
Problem two the way the device is set up (you hold it sort of book orientation with one hand round it) means if you are to see the screen and use the touch screen you tend to bend your wrist at an odd angle. which can be quite painful after a while, the alternative is to not be able to see the screen properly.
Problem three and it may just be my hands here but strapped in to the grip thing with fingers arranged on the buttons gave me sever hand pain after about half a song. To the extend that it was too uncomfortable to play, fiddling with the setup I found other more comfortable ways to hold the thing but usually only and compromising ability to hit the buttons or making it too easy to dislodge the button addon.
Problem four the set up for the mic to trigger star power is so sensitive (even on the lowest sensitivity setting) that it just goes off at random when you filled the bar. The music itself or the taps on the screen are enough to trigger it. So star power is basically useless.
It really is a shame because as a concept it's great and when the game works it is like playing GH in the palm of your hand. I might see it I can hack the controller add on to make it more usable or better yet maybe take it apart and see if I can build my own, it is after all just a few buttons wired to a bit of edge connector.