It's awesome. I really felt "at home" there. Everyone was really nice and nobody was condescending, so people of all skill levels can go and have fun (and learn). It's really cool to be walking down a hallway or standing in an elevator and overhear snatches of conversation that include words like "buffer overflow" or "TOCTOU". It's kind of hard going back to your normal life after something like that
There are tons of talks. Five going on simultaneously at any given time, most were around an hour long. From 10 AM to around 9 PM. That's a lot of information. You really have to decide what you want to make sure you hear beforehand, because there's just so much to take in. There are also lots of events (CTF, trivia games, build contests [last year it was airsoft turrets], etc) that you can enroll to participate in. The only downside to this, that I've heard, is you end up missing out on a lot of the convention, so it's probably the kind of thing that you're best to leave for your third or fourth def con experience.
It's a shame that it's on the other side of the continent, which is why I wasn't able to go this year, but the trip is the only real cost at least, not admission. Admission is $100 for all three days, and you get a wicked cool badge out of the deal (I seriously don't know how they manage to give these way and still cover their costs). Last year it was a circuit board with a 90-some-odd LED array that you used the built in touch-sensitive buttons to program whatever scrolling saying you want. They also released all the hardware schematics and code for the microcontroller with it, so people hacked up all kinds of cool projects with their badges. I saw one guy with Conway's "game of life" playing on his. There's a badge hacking contest, I think last year's winner incorporated an audio input into theirs and turned the badge into an equalizer.
I'm probably rambling at this point. Anyway, the gist is, it's awesome and anyone remotely interested in hacking should go. the only thing I'd probably do different is go with friends next time. I probably learned more going alone, but if you have geeky friends I'm sure it would be a blast.