A couple thoughts that in my opinion keep Guitar Hero III from besting the original Guitar Hero. Check it out and see...
And quickly my comment on the controller is simply... I like it way better than the SG models. No wires and a better feel when pressing the buttons, what's not to love.
Now for the bad. The one thing that sticks out for me is the terrible oversight in the online mode to not to be able to pick from your friend list when setting up custom matches! Sure you can search for your friends name in the list of created matches, but then you have to contend with other people getting into the match before you or getting the constant message that the room is not available which brings me to the next problem for the game. The online mode at least through the PSN needs to be improved a great deal. Many times over and over again when trying to join a match you get the message 'unable to connect' or 'this session is no longer available'. Even when I've created a match I sit for several minutes waiting. The third and final beef in my opinion is the timing of the notes. Just because they included Dragon Force and a couple of other faster songs didn't mean they had to scew the timing of the notes for the whole game, especially when the Dragon Force song is not part of the single or co-op requirements to beat the game.
So in closing if you have never tried or played any of the GH games before you will not be disappointed with GH3. If you have played the others like myself you may want to hold off as there is not a lot different, but if you have been wanting to jam online with your friends then this is a must buy.