It looks good, I started writing a game in it (and it was fine, though I have no comparison with other frameworks), but it seems that no-one uses it. Or am I mistaken?
Judging from the Google group, it doesn't seem to be very active but not dead at all. The main difference with Game Closure seems to be that parts of it are native code and must be compiled and deployed to the phone, which makes it particulary interesting for speed requirements.