I recently got a GH:WoR guitar and RB3 crashes nearly half the time I try to play any song in Practice Mode. It doesn't matter if it's on disc, dlc, or RBN.
I have to reset my whole ps3 to get at it, and with RB3's insane loading time at the beginning on the ps3 version, it just ruins my will to use practice mode on that game.
I had this problem 2 years ago but it was far less frequent. However I never encounter this issue when I use the keyboard.