[simplify]

I've tried to use flow three times now, but the tooling just isn't there yet. It might be better now, but Facebook doesn't seem to invest heavily in developer UX.

[jnbiche]

What problem did you have?? I've been using Flow.js for work for several years now, to great success. I feel very uncomfortable now writing plain JS.

[simplify]

For some reason I could never get flow's in-editor errors and type information to work. Personally I use TypeScript. Their sublime support is nice and fast.