The extension is very well developed, and easy to use on the back end. I had a conflict with my template - getting it worked out. However, the responsiveness and helpfulness of their support is some of the best around.
This is a great extension that works very well. I had some conflicts/issues on one of the sites I was using the extension, and their support team was absolutely incredible (fast!) in helping getting it all resolved...and the issue wasn't even the extension's fault.