Is there any difference between the performance of pure MVC vs Classic MVC. we are building an e-commence website and want to decide which to use Pure or Classic mode in Sitefinity 7
By classic to you mean "Hybrid"?
In general PureMVC will always be faster, the markup is a fraction of what it would normally be in a webforms scenario...
I have no ACTUAL data to back it up, but I would say yes, go Pure MVC, the Sitefinity feather widgets are almost all done, and are certainly better than the webforms ones.