They arent that perfect for raiding, but if you got your own guild, you can ask them, they are strong against undeads so why not give a shot in Naxx? Holy is the way to go.
But im ret and im playing in a PvP server. Theres a hater that got a name with heal on it, that says that every ret should roll holy. He is the reason i rolled a paladin. His crusade against the ret didnt work well;) For Killerduki! *Raise sword*