Sellbrite

We have been using sellbrite for almost a year and it is a fantastic app, the only one able to help us sync our inventory, we have a collectible business and most items are unique so we needed a very good app for sync our inventory.
The customers service is fantastic, they help us sync, step by step, and when we had some questions they answer them very fast.
they are always updating they app even if it is perfect as is.