Looking at the interface, it is clean nice and simple interface. It is chrisp and fludic and quite responsive compared to any other OS. It has wide range of wedgets which shows notifications and all in nice and simplified Dock.
The features that are missing in the present OS are the Dark theme. It has beautiful translucent dropdown menu. Most of the things are controlled through commend key but it also supports gestures in the trackpad. It is the best OS by far by Apple.