best survivibality is glac priest...Due to better heals
and best single target damage is Inferno vamp...due to the DoT's
But Vs each other in a battle of the AOE doing a dragon orders?
I know inferno vamp has bat form to make Hellfire death have an epic CD/Cast...but Glac priest have prayer of frost which knocks down it's main AoE's CD by 75%...so in direct AoE i think they are around the same damage...both classes get a talent that makes mastery effect the bonus damage by x amount...
in my own personal opinion i think glac priest would win due to its HoT's..but what do you think?