I'm fire atm cuz I couldn't come close to the Shaman's as frost or Arcane. even on bosses.
But I do use Mana Gems / Evocation every cooldown.

only reason I choose a Mage if becuz I didn't want a full shaman group. and I thought the Port / Water would be usefull.
But now I'm thinking if I can get way so I don't use as much water. Screw the ports lol