Does anyone use doba.com for drop-shipping on ebay? Does it work, is it expensive and have you made money?

I am thinking about using a drop shipper but am a little hesitant. I think I understand the process correctly-I list, someone buys and pays and then I buy the product from doba and they ship it. What I am worried about is does doba ship it quicly or do they even ship it at all. There are so many scams out there I don't want to get caught up in one. They say they are registered with ebay?? I checked and they are registered with the BBB online. Any help or experience would be appreciated.