If your healers are geared enough, you should use it on a Shadow Priest, Fire Mage or Moonkin, otherwise a Resto Druid or Holy Priest are decent choices. If you don’t have the choice, use it on any class that has any kinda dots, just make sure you have that precious 3%(9%) has...
DruidFF: [Faerie Fire] FFF: [Faerie Fire (Feral)] GoW/GotW/Gift: [Gift of the Wild] HT: [Healing Touch] Inn/Innerv: [Innervate] HotW: [Heart of the Wild] LotP: [Leader of the Pack] MoW/MotW/Mark: [Mark of the Wild] NS: [Nature's Swiftness] OoC: [Omen of Clarity] Resto...