First, a disclaimer. I realize that these are totally different raids with very different healing requirements, and that's probably the reason I'm interested in the two recount totals.
This first one is from OS25 on Wednesday, Feb 11; Renew, Greater Heal, and Prayer of Mending dominate my choices. 4 healers were in the raid; Daxie was assigned OT healing, with helps on the raid and MT. We cleared everything with no wipes.
This one is from last night's Naxx10 run. The same three spells top the list, albeit in a different order. There were two healers in the raid; Daxie was assigned OT and raid, with helps on MT. We cleared Arachnid, Plague, and first two bosses from the Military quarters.
A gear factor that was different between the two raids was getting the T7 bonus of an extra jump for my Prayer of Mending (6 max jumps instead of 5).
And now, the observations.
1. As evidenced by Devouring Plague healing, I had down time where I could DPS in both raids, even though we ran both raids (technically) short on healers.
2. I still run Healbot, so I can toss out heals to anyone in the raid with just a click. If I see DPSers taking splash damage, I toss them a Renew. If they are taking more damage than just AoE stuff, I'll shield them. In the event of a significant loss of health of a DPSer, I'll Greater Heal them. This is, of course, not counting fights where people get random DoTs; these I prioritize over everything but keeping the MT and OT alive.
3. Naxx required a lot more group heals. During the Loatheb fight, I almost exclusively used Prayer of Healing and Circle of Healing. I was in the ranged group, so I'd time my PoH to hit just as the healing window opened, and I'd hit the melee group with a CoH. This strat worked out VERY well!
4. I didn't see either run as "competing" with the other healer(s), but I did adjust my healing style a bit in the Naxx run because the other healer was a Pally. Often, my Renews would get overwritten by his quick heal, so I started Flashing people (/giggle), instead of Renewing them.
5. I think I enjoyed the Naxx10 run more as it required more of me as a healer. In the OS run, one of our healers had connection issues, and we still made out fine (he didn't D/C during the last boss). Now, that said, our Naxx10 run only really required 1.5 healers for the vast majority of what we did, but the big difference was in what I needed to do, namely, more group heals as well as timing heals. This made it more interesting. There was still time to wand, though.
6. Running with Blood for Blood is a real treat! Nothing against my old guild, as they were still gearing up and organizing, but both of these runs went very smoothly with minimal wipes and no blame gaming. Once we get a bit more organized and get to where we are starting and ending on time, I'm sure that we'll be progressing through content at a fairly quick pace.
Sometimes, healing is a difficult activity to quantify. Sure, I could look at overheals, deaths, healing efficiency, and other aspects of healing, but in the end, if I'm happy with the way things went (and wasn't the cause of failing content), I'm not inclined to change anything significantly. I'm sure that I will get better with practice.
Oh, and I hear there's a big nerf coming soon to priests' mana regen. I'd hate to see that, but on the other hand, I don't think I dropped below half mana for the entire Naxx10 run. I suppose I can see why Blizzard might want to adjust that a bit.....but I like being overpowered....