I would suggest starting by checking every single band on the roster next year. Then what you can do is go back and check out the rosters of previous years; band by band. No better way to familiarize yourself with the festival, the bands, etc.
Also, this forum is THE only place on the internet where you'll find educated, insightful, eye-opening and always fun conversations about metal and music in general. All of the other forums are just breeding pits for assholes and trolls. Keep in mind the average age of the ProgPower USA attendee is well into their mid 30s if I'm not wrong (maybe higher by now?), so rest assured you won't see a bunch of bs around here. Lots of members of the forum are either in professional bands or involved with the industry one way or another, so a lot of times you'll get first-hand opinions directly from a valid source. I love this forum and (most) of the people on it.