The encryption makes this a complex subject, which an lead to the odd config issue, but this is where you really start to get your money's worth.
The level of support which Deian gives is simply remarkable. I had a problem with the encryption forcing an unwanted resize of some documents, and I had a fix within the hour. This doesn't seem unusual, as both these reviews and the extension forum are full of similar stories.
It just doesn't get any better.
Now, though,, after installing RedShop and having a fully functioning, highly (yet easily) configurable cart up and running in a couple of hours, VM has been consigned to history. It was helped greatly by the facility to import all the VM data with the click of a single button. Well done to the RedShop team for including that little gem.
I admit that my store is fairly simple, but RedShop still does it better than VM ever did. Just about the only downside I've found is , as someone else commented, the lack of multi-language support, but this is a minor gripe.