I am using Virtuemart on practically all my sites at least for a couple of years now (It used to be called Mambo phpShop) and am pretty happy with it.
However, it can still use some improvement but I am very hopeful as it benefits from having a relatively strong support community and plenty of version updates and bug fixes.
I also use the following plugin to link the CB user profiles and Virtuemart to streamline the login and purchase process:
forge.joomla.org/sf/projects/vmart_cb
I hope that it will work for you.
JD