When looking at the major survey sites out there, it's easy to find many similarities. For example, they all compensate you for your time, most of the time even if you don't qualify for a particular survey. Many of them reward you for getting your friends to sign up, and some of them even give you a little something just for becoming a member yourself. However, just because they have similar features doesn't mean they handle them all the same way. As a result, I've put together some pages detailing the sites that do the best job in a certain area.
In a perfect world you would qualify for every survey, but realistically everyone gets screened out at some point. Most of the time sites give you an entry into one of their drawings just so you won't walk away empty-handed, but not always. Some give you nothing, and some just pay you straight-up. ePoll is in the latter group. If you get invited to participate in a survey but get screened out, they still credit your account with the same amount of points as if you had finished it. How's that for taking care of their members?