I'm not him, but the Flow compiler not supporting Windows is a dealbreaker for some.

Thanks. The Flow team is planning to announce official Windows support, hopefully in the next few weeks.

Is there a reason to use Flow rather than Typescript now?

It seems to have interprocedural type inference, which is really cool, but I'm not sure that's a feature I'd even want in Typescript, since I feel like it would make code less self documenting.

Overall it seems like there is more community support for Typescript than Flow, which is essentially just group inertia, but it makes me not want to switch.