Obviously, there are still differentiators between the projects (like TypeScript including a known set of transpilers vs. Flow delegating to Babel), but I'm curious to know if they are converging on their core feature (e.g. how to do type-checking/static analysis).
It's pretty easy to see where things are going. Advanced type systems (Elm, Scala, ML, Haskell, whatever) have the features we really need, and tooling (IDE support, etc) can use that info to provide crazy good tooling, so any type system developed in 2016 and beyond must have all of these things to be of mass appeal.
If you're referring to differences in the way TypeScript narrow types based on control flow analysis, we don't see one as being "better" than the other, but TypeScript takes a more optimistic approach to avoid putting users in frustrating scenarios where the analysis is too limited. Most users tend to prefer this to the slightly more rigid approach used in Flow, so we felt we made an ideal choice there.
If you have any specific thoughts or ideas, feel free to leave us feedback on our issue tracker.
I think the javascript type system world is still evolving, and the only "wrong" thing to do is to say "Ok, its a solved problem, let's run away with THIS ONE and kill the others".
As long as we still have at least 2 reasonably well known ones, I'm happy.