The thing I find real enjoyable about tournaments is the chance to roll with someone you've never seen before. When the ref. says go, you don't know if the guy is good at jits, wrestling, super strong, a cardio freak, etc..
On whether to go or not depends on your personnal attitude. The worst that can usually happen is you get creamed. Some people can deal with that emotionally, some can't. If you can deal with it, I'd say go for it. You'll get alot of experience.
Tournaments are a blast, just be careful. If you get caught and are too stubborn, you can end up with a broken arm..