I actually just sold my pass for it, as I double booked that weekend. Not sure if you are a fan but Boston also has their "anime" convention that weekend if you like those things.
As for conventions in general I have a lot of fun at them. I love watching top level players in CS or SC2 so if they have anything like that I am usually all over it. The games are fun to play but the lines are so long and usually only give you 5-10 minutes of playtime. So I struggle playing more than one big game. I don't know if you will get any major announcements at Pax East. I don't think companies have ever used it to announce projects but that is usually awesome to see to.