Man,honestly,I dont know which is better,the songs and Guitar in Guitar Hero are awesome, but the drums are so fun,plus i'm learning how to play real drums,so thats an upper for Rock Band.

First up is Guitar Hero 3:

Pros:

1.Guitars awesome

2.Good songs

3.Harder difficulties

Cons:

1.Not good for a large group

2.Crappy Graphics

3.Career cant be played on-line

Next up is Rock Band:

Pros:

1.Good for a large group

2.Drums are funnest instrument to ever hit a rythm game

3.Awesome Graphics

4.Overall good songs

Cons:

1.Guitar notes come to slowly

2.Outrageous price

3.Has some sh***y songs

4.Career cant be played on-line