I also switched two of my research projects over to TypeScript from CoffeeScript [1,2]. I'd like to state up-front that CoffeeScript still has its merits in certain scenarios; they are two very different projects, despite both providing convenient `Class` abstractions over prototype-based inheritance.
With that said, using TypeScript has vastly decreased the amount of mental state I need to keep in my head when I develop one of my projects. The compiler uses the type annotations to double-check my logic, and Visual Studio gives me the ability to easily refactor interfaces as if I were using a statically typed language [3]. I could go on... but I will spare you the blog post. :)
I really wish there was a free or cross-platform alternative to Visual Studio for TypeScript autocomplete and IntelliSense. The WebStorm IDE claims to support TypeScript, but it gives me tons of incorrect compilation errors in my current projects. I hope it matures so there is an alternative. Anyone working on TypeScript tooling that is comparable to VS for different editors (e.g. Sublime)?
EDIT: Whoa, I completely missed this in the blog post; palantir is developing an Eclipse plugin [4]. They also developed a tool that converts CoffeeScript projects to TypeScript; interesting [5].
[1] https://github.com/int3/doppio Doppio: A JVM in TypeScript
[2] https://github.com/jvilk/BrowserFS BrowserFS: A full-featured file-system in your browser that emulates the Node fs API
[3] I'm referring to trivial refactorings -- renaming function/variable names and such. Refactors that are more complex, such as changing the function signature, must be done manually at call sites, but the compiler will catch your errors if you mess up or forget one.
[4] https://github.com/palantir/eclipse-typescript
[5] https://github.com/palantir/coffeescript-to-typescript