During RAF, I got 5x Druids, Hunters, Shamans and Priests, each to 60th.

The priests are/were Discipline primarily, with a little Shadow.
Shaman's leveled easier, with 5x mana totem and water shields.
Priests were faster then Druids or 5x BM Hunters, although solo the hunter is my fastest leveling class.

With pretty crappy gear, 5x Holy Nova is enough to kill just about any mob before mana goes.
Shadow was only deep enough for Mind Flay, and I believe in Holy only took the talent to improve Renew; everything else Discipline.
The castsequence for PW: Shield was a pain to set up, they need to be in your party/raid for the spell to land, which made me think it was a broken macro for a while.
Instant AoE fear on a castsequence is strong, PvE, but it seems everyone has fear immunity for PvP.
I used a cast sequence to sequentially give Fear Warding to my current leader, who can very quickly cast Mass Dispel on the group vs a fear bomb.
5x Mana Drain will be strong against players.
5x Prayer of Mending will help a bit, and priests have good aoe heals.

Have not actually PvP'd with them yet.