I actually played this for the first time last night, and I thought it was an all round terrible learning tool. I was playing Cemetery Gates absolutely 100% correctly, since, you know, I've been playing that song for about half my life now, and it was telling me I was 'wrong' because I wasn't striking the singular notes they'd picked out (in an effort to make it simpler).
It's one thing playing simplified, root-note-only versions of songs, but it isn't going to get you anywhere.
However, I did watch my bassist play the game for a bit, and for bass it seemed much much better.
And agreed, terrible sound banks, they could easily have worked with someone half-decent for that.