I use it on Rage Winterchill, he has a frost bolt that hits for 4250-5750 damage and then 2500 damage per second for 4 seconds. Intensive to say the least but with target of target spam and the fact that Rage targets the person a half second ahead of cast you can heal the guy before you even know you're healing the guy.
It made the fight easier and I liked. I then decided to use it in random aggro fights like Aran or his big sister Solarian. I topped meters doing nothing more than pressing 1 button the entire fight.
Today I really fell in love with it.
10+ t6/s3 equipped horde walked into IF today and started roughing people up. Including perhaps the most feared Tauren Warrior on the server. Now healing through such a big brawl with no raid ui suuuuuuuuuuuuucks. So I just targeted the big bad War and started spamming target of target. It was perhaps the most amusing thing in the world. I could see him starting to get desperate and finally I could see him cycling through people trying to lose the healer only to find me on him every single step of the way. Completely neutered his dps and with the warrior out of the fight things got a little more enjoyable and we started corpse camping some horde.