Pros
Very streamlined portal and easy to use interface. Sometimes the topics are interesting. You can work when, where, and how much you want.
Cons
There is a significant learning curve in which you will complete lots of work for which you are not paid. They do not allow for revision of work and simply don't pay you if your work is not accepted. This is counter to every other contract gig I've ever had. Some of the requests cannot be fulfilled by information the Internet. This is why people are paying the $75! They need to give analysts log-in subscriptions to databases where this information can actually be found or allow them to say they have searched for x length of time and the information is just not there. It is very frustrating to spend three or four hours on a project and then get paid nothing because the request was beyond the scope of information available online.