About 98 features are ported. I cannot say 100 because the thread related APIs haven’t been wrapped, async operations are not supported yet, but you can do it by yourself. Please run and check the cocos2d-x/tests, it inclues all features.
Here’s the published game list in http://www.cocos2d-x.org/projects/cocos2d-x/apps, including many games from big companies.
Porting objc to c++ is an easy work, the average speed is about 500~800 lines per man-day, while the guys from “Ah Up” said they ported 3000 lines in just 2 day.
The pain is from android ndk debugging. I suggest you to use win32 port first, debug in VisualStudio, and build to android at the last. It will make porting job easier.