If you're looking for a product that will not allow you to oversell on eBay or Amazon then this is product for you. Does a very good job of syncing inventory. Other than that it sucks.
Overall I really hated using Sellbrite and we used it for over two years. It's slow and designed poorly. Try to find useful data to make decisions then good luck. Search is slow. Adding items is slow and painful. You are much better off entering items directly on the channel itself because Sellbrite is slow and limited.
So many better choices than Sellbrite nowadays. . I am using something else now but I won't say because every business is different. My only advice is to REALLY take advantage of the trial period when testing software.
Bottom line. You will not be able to grow with this product.
I tried to cancel my account and they put me through hell. We were with them for two years and I didn't expect them to make it so difficult for me. Not a classy move on their part!