I have used this plugin on about 5 different sites. They were all working great, and then recently they are all having major problems. At checkout the customer can't finish checkout because there is a continuos loop sending them back to the beginning every time they click anything, so customers can't finish checking out. We are now trying to switch all of our customers over to use woo commerce, because the support is also non existent. I was hoping with the most recent update that some of the bugs would be fixed, but they weren't.
To all those out there, just avoid this plugin, it looks enticing, but will be nothing but headaches for you in the long run.