I would give 5 stars, but eSync does need a couple more features which they are working on. I like that they do listen and will put feature requests customers absolutely need in the front of others. This software helped us with our brick and mortar multi store locations with Magento and Revel Systems cloud POS. We can now send all of our inventory to each unique Magento Web Store which is awesome. Some logistics for setup of our five locations, but once done this is an amazing integration. Magento is a resource HOG, so make sure you optimize your server so it will accept all the data that's being updated constantly from Revel, otherwise your server will go down. We updated our Max SQL connections from 50 to 300, along with a few other optimized settings and everything works great! Great software, absolutely needed by any brick and mortar store that needs an eCommerce and Amazon, eBay integration.