Karma and PvP system is fucked up on almost all Private servers (Stuff like: Healers don't flag if they heal a flagged person). And the Sin Eater is not implented. I see no point in playing on a private server to PvP. It's much more fun on retail, with voice communication and a good clanwar.
And x1 is more fun. O RLY? YA RLY! I also thought OMGWTF x1 t3h hard when i played private, but that's wrong. x1 ftw.