I have no problem forking over the $ for this track pack if the songs can be played from my Rock Band 2 disc in the drive (i.e., no disc swapping needed).
You know, at first I was really disappointed by this being live tracks and not the studio versions, but then I thought about it, and the game pipes in artificial crowd noise anyways, and there's already crowd singing along with you for all the other songs. Now those sound effects will be real instead of artificial.
I'm not going to knock it until I try it in-game, but I have a feeling this might be the only medium where a live version of a song could be as good or (dare I say it) better than a studio track? The live version should be more immersive for a video game where you're imagining yourself as the performer.