Because they actually help you out. I promote several programs, MakingCoin and Weconvert. MakingCoin always helps out, and weconvert goes above and beyond to work with me on stuff. Suprisingly enough, BangBros hasn't helped me with a damn thing I needed. I get the best conversions with weconvert .. average of 1:18 to 1:50~ ... whereas bangbros I am 1:150 to 1:500 easy. Sorry .. just had to say this about them.
You must check them out:
http://www.weconvert.com
http://www.makingcoin.com