Typed Racket (due to different integration into the compiler) is much more incremental -- the speed issues in the blog post would be much reduced. The typecheck

Typed Racket (due to different integration into the compiler) is much more incremental -- the speed issues in the blog post would be much reduced. The typechecker still isn't as fast as we would like, though, although we have plans to improve it. I think the tooling integration is better in Typed Racket, although Ambrose has made some improvements in Typed Clojure as well. As for typed versions of existing libraries, I think that things are bit better in Typed Racket, but also Racket has many fewer libraries than Clojure at the moment, so the scale of the problem is smaller.