This is a must-have for EVERY Joomla user. Never worry about losing your data or having to transfer your website again.
HikaShop was recommended by someone on the VM forum (who was also having problems getting VM to work) and so I decided to give it a try. Within 1 hour after downloading it I had a basic functioning webshop! It just works. After the gruesome fiddling with countless parameters in VM, setting up HikaShop was a breeze.
It's simple to setup, yet still offers a LOT of options and functionality for more advanced users. And for users who really want to take full advantage of some powerful features, there are the commercial versions that are very reasonably priced. Plus, any questions I posted on the forum were answered within hours, which is more than I can say of the VM forum.
I'm sticking with HikaShop, and upgrading to the Business version soon.