I've been to two fests--06 and 07--and both were great experiences for me where I met people from this board (hi retzev!!!) and talked with tons of others who may or may not be on this board. The actors are all very open and welcoming, some certainly more than others (usually those who aren't exhausted from huge lines, and thusly have some extra time to sit and chat), and will talk to you for quite some time if they're free.
During my first fest, John Karlen moved from table to table to table at the banquet, talking to everyone (the actors usually sit with people they know or are familiar with at the banquet) and having a great time. Also, at the same fest, my mom and I split up to get autographs and stuff in different lines, and when my mom went to Jerry Lacy's line and asked him to sign my book, he asked if I was unable to attend. When she told him that I was there, but we had split up to get autographs, he told her to make sure she brought me by to meet him later. That was nice, to be sure, but when I went by later and purchased one of his photos, I asked him to make it out to "Brandon". He looked up and smiled, and seeing my mother, said "Well, I'm glad you got a chance to come by the table," then proceeded to have a short conversation with me, even though there was a line. (The other stars do the same, which can make the autograph lines horribly long sometimes).
The only downfall to the fests are the lines, but, as someone mentioned earlier, they are a great place to get to know people and make new friends. The banquet line, the registration line, and the autograph lines (if you hit them at peak times) can last for HOURS on end, but if you don't mind waiting and standing, they're great.
I'm sure you'll have a great time when you get to go, and I'm hoping to go again next year as well since I was unable to make it this year.