Hi amsols,
Welcome to 5 star and thanks for starting a poll. FYI none of those companies are really management companies, they are more networks. Networks provide the tracking and infrastructure and have some affiliates - but just so you know they don't really manage your program or do outbound recruiting for you.
So if you are asking about networks, there is one that many affiliates really like called Shareasale that is my preferred network to refer merchants to these days. Here is all the info. Only 150 set up cost too.
http://shareasale.5staraffiliateprograms.com
Hope this helps and best of luck!