I've always played DPS in my time playing WoW. I recently rolled a holy priest and am interested in the HPS game. The add-on the healer in this video is using seems to be super efficient:
Image found in this video, containing a spoiler strategy for defeating Hagara in the Dragon Soul raid on heroic mode. If you do not want to have this spoiled for you, avoid watching the video.
Can anyone vouch for what it is? Or give an answer for some AddOns I can download that are very popular with healing types, particularly priests?