I agree fully with what Robfamfirt had to say in his post. There are some nice features to Doba. They have a push to marketplace tool so you can easily push any item in their inventory straight out to an EBay auction under your account, the educational tools are good, and the wholesale/retail listings are nice. They also have a large selection of products. As Robfamfirst said though every item they sell is being sold by other members on EBay and the competition is too steep. Also since Doba is not technically a true wholesaler/dropshipper, but what I have heard referred to as an aggregator you are paying slightly higher than wholesale prices. How can you compete on EBay which is a below wholesale-wholesale market with above wholesale prices? The answer is simple - you can't. Sure you might find a few gems in their invenotry that will yield some small profit from time to time, but it won't be long until joe blow small time seller or newbie comes along and starts selling those items for less than you are through his Doba account. Doba might be a good source for selling on another site, namely your own, but your not going to build a solid online business with Doba selling on EBay. Just my 2 cents.
BTW - if you want to trial Doba for 14 days cancel your subscription form right in the middle of filling it out and you'll get a popup with a 14 day offer. That will give you a little more time if you want to try your hand at listing any of their items.