Oh, Blizzard, how difficult you make our lives. Priests who choose to specialize in healing have a certain dilemma between Improved Divine Healing (IDH) and Empowered Healing (EH). Healbots get to choose between these two different builds.

IDH is a group buff that increases spell damage and healing by 10% of the caster's total spirit plus Divine Spirit which increases Spirit by x for a period of time. EH, on the other hand buffs Greater Heal and Flash Heal.

The difference between the two becomes apparent when you check the spell target/s. IDH concentrates on group buffs while EH focuses on single target heals. The IDH build may be loads better when you're on a raid, just group grinding, or in group instances. Plus the other casters in the group would love you. The EH build would grant you more healing capabilities Greater and Flash Heal.

You can't be fickle. Well, the choice depends on what results you want in the long run. Personally, we'd just roll a 'lock.