The healing classes are very well balanced. Many, many very good and knowledgeable people consider Sages/Sorcerers the best healer in game. Personally not being overly good or knowledgeable I consider Operatives/Scoundrels to be the best healer in the game, but even as bias as I am, I know that Sages/Sorcerers have the best AoE heal in the game. In PvE, a Sage/Scoundrel or Sorcerer/Operative team is a very powerful healing team. Again some progression groups think those are the go to combination. Again I disagree, while that is my favorite combination, I don’t care what other class I play with. All healing classes are more than capable of getting a group through any content in the game provided the person behind the class understands their role and their class abilities.
Depends on what you are doing, PvE rewards for Operations are the best you can get in game, for PvE. Same goes for PvP, the reward you get there is the best you can get for PvP.