I recently had to install and configure this plugin for a client to sync WordPress with QuickBooks. Unfortunately it was just after the 1.9 release and it immediately broke the site. I found the support guys to be fantastic in resolving this matter (I highly suspect the 1.9.1 and 1.9.2 releases were due to feedback I gave them) and when I ran into the snag with the configuration afterwards they were only too happy to help. Everything is now running perfectly and the client is delighted. Highly recommend this plugin!