We've created a page with highlights of the new release as well as a link at the bottom with the full list of changes.
http://www.3dcart.com/v3.html
Additionally we've created a new 30 day trial page (also on the bottom of the V3.html page) for you guys to test V3 before your stores are migrated. (Just scroll all the way to the bottom to find the 2 buttons)
If you encounter any issues please submit a support request to
support@3dcart.com.