Does anyone have experience with an outsourcing website to help search for emails/owner names?  I have a few interns working diligently on this, but I'm wondering if there are specialists out there who can gather this data faster and more efficiently.

Some of the sites I'm considering:

In addition, what sourcing processes have worked the best?  I've been using Reference USA and to find company names and websites then I use Email Hunter to try to find the owner's email.  Are there sites, programs, or processes that anyone recommends I try?

Any insight would be greatly appreciated.

-Gus Gabel