I totally agree with you with regards to the language itself sharing similarities with C#, and you make a good point about avoiding all the FFI native calls hassle.

I couldn't find a whole lot of independent benchmarks but I'd suspect that at least in Chrome, it does outperform V8.

I guess I'm just not the target developer for this, though. If I want optional static types I can implement typescript incrementally into my existing stack, while retaining the code portability benefits. For desktop apps, NW.js is aiming to plug that gap, and I wouldn't have to give up my npm modules.

Another poster mentioned waiting until it sees a push at Google I/O before taking it seriously. I'd settle for them just to explain the problem case that drove it's development.

EDIT: I hadn't spotted harryf's reply below that makes the point about transparency better than I have above, kudos.