If you want to use VM you are on your own, from template bugs, payment not working, and good luck getting the shopping card working.
It is old out of date and time to put out of its pain.
The problem is there is nothing for Joomla that can do a e-commerce. so if you are looking to make a "real" store good luck hunting.
I think even the developers gave up on VM, shame could of got to the top with it.
Hope someone take over or reinvent it.
Maybe few sites can use it without the CB but it is a must for this component to be rated as HOT.
Also more rewards and options would be nice.
Overall solid work but not mature yet
Please, check my forum and read the changelog: I have included registration with CB in the version 0.9.13. And the plugin tab for CB already exists.