I've played both and honestly Rock Band 2 is way better. Activision destroyed GHWT.
I do not see how it is destroyed. I have been playing the Guitar Hero games since they were just demos in Best Buy and it wasn't out yet. GH3 is the worst of the series but it is still fun.
GHWT brings the ability to create your own guitars, create your player, create your own music or input real music. It introduces appreggegios into the game as well. A very innovative gameplay function that introduces real life techniques to gaming. The song list is awesome and is very large right out of the box. 86 songs to start with and DLC available.
The game has multiple difficulty levels to allow gamers of all different abilities to enjoy it. The drums are wireless out of the box. The guitar is wireless out of the box. The microphone can't be wireless as vocals could not affordably be done wirelessly. You can import MIDI files in the GHtunes feature, you can hook up your own electronic drum set if you have one. You can download unlimited user created songs provided you have space on your hard drive.
My only complaint is the pressure sensitive drums require a different playstyle than Rockbands. They need to be hit hard. Thankfully they are quieter than RB's and can withstand the pounding. Have you seen the video of Travis Barker playing them? he is beating on them like real drums. The touch sensitive slide section on the guitar allows for slap bass, tapping, slide guitar and is very innovative.
I played RB2. They song list is good. The instruments are nice but it is not as innovative as GHWT. That does not mean RB2 is a bad game but at a cost of $200 or so I would rather buy the standalone RB2 game and buy the whole GHWT kit. The GHWT instruments are better quality and more innovative.
I can't see how it is broken. It is the best so far. Prove me wrong.