Currently, the Hammerhead is in development and is supported. There are three types of roms.
Alpha: Means the rom is in the early stages and is not recommended. These roms may not even boot!
Beta: The rom has gained some stability and does most likely boot. These roms are only recommended for people who want to help by leaving feedback.
Stable: These roms are stable and will boot. These are recommended for anyone who has a rooted device.