I only ended up logging on for part of the day on Saturday due to real-world commitments. Boo. Hiss.
Since I had limited time, I stuck with PVE. I didn't bother with the main questline, but opted to run amok and check out the dynamic events. I tried most of the classes for a bit (Greatsword Mesmer was a blast), but I ended up focusing primarily on the Ranger, the Guardian, and the Elementalist.
Ranger was a lot of fun. It was a little different from most "hunter" types I've played before, which created a nice bit of a learning curve. Had I more time, I would have tried out some more weapons options. I'll be focusing on the Ranger some more during the next BWE.
Guardian was awesome. Let me say that again. Awesome! I used a hammer as soon as I could, and I felt like a god. I loved combat with the Guardian. It felt like I was actually "messing sh** up" and not just swinging around a giant, featherweight, 2-handed hammer. I'll definitely be playing one at launch.
The Elementalist was everything I wanted in a magic user and more. The attunements were wonderful. The healer in me liked Water; I had fun healing some of the tougher dynamic events. I tried to push my limits with the Elementalist, switching in and out of various attunements during combat and figuring out what worked best with what. With my staff, I found myself spending a lot of time going from fire (initial dmg) to water (snare/quickie heal) to air (knockback) to fire (finish em off). I'm pretty sure the Elementalist will be my main class at launch.
(edit: I'd also like to state that if anyone loved the Druid class in WoW -- but couldn't find anything remotely similar to it in other games -- ought to give the Elementalist a whirl.)
I'd love to hear what the rest of you thought about the classes you played.