In a personal opinion?
I'd have to say it would really depend on the situation They seem about equal to me. Bats have birds beat on night flying, but birds have bats beat when it comes to proper landing gear; and the wide range of beat styles allow fo a multiple diet on a single species. Such as eating nuts and insects.
All in all, a bird would be the obvious choice. But like I said, it depends on the situation, and what a persons preference is, I guess.