alpharomio

I need one more clarification , i have found that few casinos websites are directly offering their affiliations e.g queenvegas affiliate programe is under affiliates qvaff , and on the other hand there are certain affiliates sites like affpower which are connected with various casinos .
 
what is the difference and which one is better 
 
i would appreciate if someone can guide me in details, i am bit confused being new to this business.
 
Thanks 
 
AR