Don't get me wrong, I have a huge appreciation for Esperanto, but using it as a global language would mean forcing western ideas, about how a language should work, on the eastern population. So as Zamenhof didn't consider Asian languages when he made Esperanto (not to mention the use of diacritics), I wouldn't use it as a global language.

I have been following some auxlangs for some time now, and if I had to vote, I'd go with an a priori language as a global second language, instead of choosing an existing one with specific culture attached to it.