Consider only heal pve, as a player that knows how to play with both powers. Don´t consider playstyle, combos, etc, only which one is better. Vote 1 for Nature Vote 2 For Celestial
As long as everyone stays alive it doesnt matter which power is considered better. With support roles most powers do great. Dps is the only area where some are usually better than the rest
McB is the single most power efficient heal in the game. The nerf to it in PvP is a large part of why Celestial suffers as a healing power in PvP currently.
McB isn't the best in SM because of CR differential. I agree though with the right spec celestial is very power efficient.
Even in SM, it still the most efficient, especially since the AM has been added to the Healer Role. Also, since there are plans to eventually remove the cr differential, McB will become even more efficient.
Nature everywhere but in SM. Nature is still good in SM but Celestials range is better situated for healing across large areas. I see lots of people saying celestial over nature but with nature you can heal the entire group with the press of one button over and over. Celestial is a great power but it just simply doesn't have the healing out or reliability nature does. If your AcB gets interrupted you end up having to do it again and using twice the power. Divine light is a great group heal but has a kinda longish cool down where as with nature i can do that type of heal any time i need to. Both are great powers but i give a slight edge to nature in everything but SM.
Tbh I think the pros and cons of each power balances them out. These two are both easily the strongest healing powers. Celestial has the range and nature has the higher healing potential. I think sorcery is fine too. Electricity is the only healing power that falls short in every category. It's power hungry, limited range and it's healing outage is not high.
I know electric wasn't part of the question, but with Bio up at all times, electric is t g e mist efficient