Heh yeah i've played this. its good fun.
As a musician i don't think its quite as bad as people make it out to be. If you play the guitar on medium/hard its pretty good excersise for your left hand (for shredding or general co-ordination).
The drums are very cool as well, i expect the hard settings are more like actual drum beats - and you can plug the drums into your PC to act as a MIDI controller! So you can program drum beats in MIDI using the funny little kit!