My vote goes entirely to the most active healer. Which I hear is Inori. And seeing as your a bitchin healer already...
The hammer gives you a buff (10% proc chance 45 second ICD) for 15 seconds that gives whoever your healing a 15% shield off the healing you do. It can't proc from OH (as i understand it) but it does still add to the shield. As the shield stacks with itself. Just like the disc shield does.
Disc priest is a single target healer, yes you shield, but you also heal one person for a crapload really quickly. Besides... say you get the nifty buff... and you get a nice 13k gheal crit, so you get the disc shield as well... toss a PW:S on em and hey you just stopped like 30k dmg.
"Example 1: A paladin casts Holy Light for 10K on the tank, which partially heals her. The Blessing procs, so the paladin’s Holy Light immediately causes a shield on the tank which will now absorb 1500 damage. The tank dodges the next two hits, so no damage is absorbed. The paladin then casts another heal for 8K, but only heals the tank for 600 before she is at full health. The shield is now at 2700 damage absorbed (1500 + 1200) for 8 sec." <---- Blue post
http://www.wowhead.com/?item=46017#comments
In essence. I Nominate Inori. now be quiet and take it like a man!
(BTW sorry I dont know a lot of you and I'm new an all that jazz. But this mace looks steller for any healer of any class of any spec. Therefore it should, imo, go to the highest attending healer, period.)