I went last year for the first weekend and I wouldn't say that it was super busy, but if you are making the trip solely for the weekend or concentrating on all things star wars, you can get everything done in a day and a half (Friday and Saturday). If you are staying at a Disney resort, save all your shopping at Tatooine Traders until Saturday during early entry. We seriously waited in line for an hour to check out on Friday adn that was completely avoiding the pin line. The autograph sessions filled quickly, but if you are not interested in getting those, you can just go over and get signed up for the trivia events.
The WWTBAM is awesome with the Star Wars trivia. I went to several sessions, but I did see a 17 y/o boy rock through the questions using one lifeline on a stupid question that had nothing to do with Star Wars to win the cruise. They give out the normal prizes plus the extra stuff. It is totally cool and the questions are answerable if you have seen the movies a couple of times.