I felt the same way when I switched from CoffeeScript to TypeScript but the type checking was worth all the braces, returns and lack of existential operator. If CoffeeScript added an (optional) type system I'd switch back in an instant.
But wow, "not elegant" is an understatement.
The home page talks a little about achieving this by using Flow annotations in Coffeescript source and then having the build system pass the Javascript output to Flow: http://coffeescript.org/#type-annotations
It is a dilemma, but so far I have gotten by without type-checking.
(I'm joking, but actually.. why not?)
Good interop with Flow isn't quite there yet, though.