Never been to PAX... for that matter I've never been to Boston. But if more tickets to this gig open up, I'm going to have to think really hard. I mean, this could very well be the last big hurrah for Rock Band.
Only catch is I'd have to make the trip alone. I'm easily the biggest gaming freak among all my friends and family, and none of them would consider it worth the money. The idea of going solo is more than a bit daunting, but, still... Rock Band!
FS - I'm not even a gamer (Rock Band and Lego games are pretty much the extent of my gaming). I would typically never go to a convention like this, but would consider this year for the RB reasons you've mentioned.
"Rock Band is literally a house full of cheese burgers" - Aaron Trites, 2nd Earl of Community