What percentage of Rhino V5 users upgraded to V6?

Hi,
Rhino v5 had some good plugins like Autodesk Shape Modeling. Now, in v6, we cannot install Autodesk Shape Modeling because it’s no longer developed. What is the best practice for those who wants to continue class A surfacing?
Do we need to get rid of Rhino and move into Alias, or do we need to stick to old version, v5, and use Autodesk Shape Modeling?