The 11 is better.
The Cloud 11
Offers the best performance with some added features
Bottom plate is designed with deeper wells to provide an added level of safety in use. The ball stays in the well and rests squarely on the dimple thus preventing the top from rolling off of the bottom plate.
The top plate features a thicker skirt that makes the platform for increased rigidity and the ability to support heavier components
The extra thickness of the bottom plate and the top plate skirt improve vibration reduction performance to an average of 99% of the vibration from 5Hz to 500 Hz, with a resonant frequency of around 13 Hz