TypeScript is very nice. The one main problem it has is lack of type definitions for third-party modules, some developers find having to "waste time" writing those defs themselves to be quite bothersome.

Typescript gives you an "out" to type checking using the any type. Additionally, most libraries really worth using have .d.ts files floating around the internet somewhere, in DefinitelyTyped or otherwise.

That's all true. It's a chicken-and-egg problem there, though. I've seen several arguments that the language is not worth looking into until more typings become available, and of course those naysayers are not going to write the missing typings.