I'm on Behemoth. On weekdays before noon things are fairly quiet (still no issue doing raids and dungeons, just not quite so packed and whatever FC you're in may not have a LOT of people online at once). Later though it gets very active and sometimes has a small queue to log on. On the weekends you are almost certain to have a queue of 10 or 20 people to log on.

Basically, it's a busy server but not so busy that character creation is often closed.