I only do PvE for aesthetic gear or to get PvE gear for my healer companion so I can do the dailies for credits faster.
I prefer PvP because people are just all around calmer. In PvE you get those micro-managers with anger issues ready to dole out blame to everyone even though most times they're the real problem. They act like every wipe (Even minor ones) are the end of the freakin' world.
Sure, sometimes you get a cranky PvP player, but they're usually PvE players, in PvE gear and getting rolled because they have no Expertise (And yet, they're blaming the entire team because they can't cap/defend a node). I have some rage quitters leave, blasting the whole team as they make their grand departure, only to have our team rally for the win.
I don't pug much but when I do I tend to believe the angry people in /ops are only being angry for the sake of their own ego :P "omgz'd you guse r so bad" = "I'm not the reason we're losing WHO AGREES WITH ME?"