I may have got slightly addicted too...
Completed with Witch Doctor, Demon Hunter, Barbarian & Monk. Maxed Witch Doctor and Demon Hunter. Wanted to complete it with Wizard too, but they shut the servers before I went to bed and then I was working until the servers closed for the end of Open Beta
Demon Hunter and Monk seem a little over powered. I hardly ever took damage on my Demon Hunter because of the damage I could dole out at range (Rapid Fire ftw). Managed to get a 110 kill streak on Jar of Souls with the Monk, which seemed slightly silly - and that was only at level 7ish. Witch Doctor and Barbarian seem pretty well balanced, however.
Did anyone get to try co-op? I felt the difficulty scaled pretty well. Nightmarish monsters around most corners with one co-op buddy but they seemed pretty easy to kill if you both used your skills together.
