Yoooo, today is great day to start testing on a upgrade from low version and all new features.
I will try to give you more and more on the features testing and how to implement it
12cR2 New Features
Video - Ask Tom Answer Team
Shortcut to the features
Oracle Database 12c Features and Products
Useful White Paper
White Paper: Transforming Data Management
If you have any feedback on some of the new features and you would like to test based on your use cases, please contact me and i will be more than happy to join!