Anders (and the people he works with) has a track record of producing useful pragmatic tools/languages that help developers develop going back about 3 decades.
I've yet to find anything he's done/worked on that I don't like, one of my programming heroes actually.
Even if you don't believe in the old Unix adage that "worse is better", Typescript today isn't that demonstrably worse than Flow. Depending on your metrics, such as general availability of community-supported type information, Typescript in increasing ways better.