It works well, it seems fast and its very, very easy to use the admin backend to tweek its behaviour for your site.
There was an issue with the Ajax add-to-cart feature in Virtuemart which I fixed after ten minutes of searching in the support forum at Anything Digital. The changes required a few code changes, but were simply to do.
*** Note that, as the author warns, if you want to use the rewrite features of Apache to remove the display of 'index.php' in your URL's, you must ensure you have this working with standard Joomla first. Otherwise, the system still works well without Apache rewrites. ***
I think this extension is worth its price tag for the security feature alone.