Dragbat is a lot of the time better than zap dragons (th12)
I know how revered zap dragons is at th12, but a lot of bases are just running single infernos, and you usually can't zap the air defense with it. I am finding more success with Dragbat in these situations
I think I'd only even consider zap dragon if there was an air defense and air sweeper right next to each other so I could take out both at once.
Depending on the base, dragbat scales up a lot more nicely up into even the TH15 meta.
I am braindead when i play CoC so i always run Zap Dragons LOL