Both were pretty fun, needless to say I was VERY rough with them. I liked the barb better, however, I have one complaint. As the barb I basically felt like it was cool down wars. If the person you were fighting had their absorb skill off cool down and yours was on cool down, you basically just lost.
I understand there is obviously some strategy to this, not engaging while on cool down being the most obvious. But the Wrath of the Berserker, and Ignore Pain skills both have relatively massive cool downs (120 and 60 seconds respectively) forcing players to avoid combat for minutes at a time. This is something I feel could be improved upon.
The ranged characters also seemed to dominate the PvP matches, but I assume that's only because they are easier to pick up and play.
Either way the PvP was amazingly fun and competitive. I can't wait to see it in its more evolved forms when and after the game is released. I really hope they keep PvP games 8 or more players, as opposed to the 4 from what we have been told.