I haven't been around for 3 years, so I don't know what things were like back then. But I can tell you that I, personally, have had little trouble with griefers. Of course they pop up every once in a while, but most of the times their annoyances are temporary, and you won't see them again.
The biggest problem I have is people who have no idea how to work on a team (or how to do anything else, for that matter), will not respond to anything, and won't talk. Stay away from crowded servers, and that's not much of a problem.
In general, the Tremulous player community is one of the best ones I've been a part of.
Hopefully you won't have so much trouble this time.