I normally stay clear of all things Microsoft. I also groaned a little when I first heard about this project. But after taking time to look things over, I'm becoming a TypeScript convert.
Things I like ..
2. Declaration files for existing JS. The --declarations flag on tsc is also very useful.
3. Interfaces as signatures.
3.5. Giving object literals inferred Interfaces
4. Switching between AMD and commonjs at compile-time
5. Inline with future ES standards. Arrow syntax!
6. The ability to unify a JS style within a group.
Please, please don't start throwing the kitchen sink of features at TypeScript. It's a perfect start. Future development should only been minor tweak here and there. Please don't cave to pressure to add a features that doen't match
the (perceived) mission of TypeScript.
P.S. Intellisense for Mac (Intellisense for Sublime Text 2) ;)