Right now I'm not sure...
I'd say yes. I'm using it. I know for a fact that Universal are using it on some of their (thousands of) sites. I will add some caveats, however:
I'm not guaranteeing every last "out-there" feature works, but the point of the system is actually to keep it simple.
Compared to vanilla ASP.NET, it's an absolute joy. I assure you that you won't miss viewstate.