Although there are already many reviews of Worldwide Brands and Doba, there are not that many articles which directly compare the two leading sources of suppliers, so that's what I'm preparing to do in this post.
Worldwide Brands is the oldest and largest directory of certified suppliers – with more than 8,000 wholesalers and drop shippers and about 16 million products it has by far the largest number of suppliers and products. Membership is expensive though at $299 for lifetime access, but this comes with extras like support and forum access.
Doba is quite different – not only does it not list any wholesalers (only drop shippers) it only allows you to have goods delivered to address in the United States. However, what it does do – it does very well. Doba specialises in drop shipping, and has become a one stop shop for anyone running a drop shipping business. Simply search for the products you want and import them to your store. When you get an order, just buy it though Doba and it will be drop shipped directly to your customer. Doba is expensive at $29 a month for the cheapest membership option.
So, in short, while Worldwide Brands is more versatile and larger (and cheaper in the long term) Doba is much easier to use – so you will pay more, but it could save you time.