Feral druids, affliction/demo warlocks, survival hunters, arcane mages, MW Monks and every DK spec seems to be lagging behind atm.
Generally speaking if your a monk/rogue/mage/boomy you'll have a much easier time getting into groups atm. But yeah most specs seem to be performing pretty well, things defiantly seem more balanced than usual at the moment. Hell Ret Paladins are even good, I don't think I can remember a time since WotLK where that was the case.