I'll be careful not to tell anyone not to use Flow - we're using many of Facebook's tools and we're grateful for their gifts to the community. If Flow works for people, that's great!

That said, back when we got started, we found that TypeScript is all around a better team player. For us, we found that it worked better with npm modules, different operating systems, vanilla JavaScript, and various coding tools (VIM, Visual Studio Code, Atom, etc).