hmmm, this is certainly an interesting question, and caused me to take a few and ponder. I agree with junglepet, that this is the kind of question that can get guys like me in trouble, but here goes. I assume the criteria to determine what attributes makes the best would be subjective to the reviewer. To this end, my criteria is how creative She is/was; how in control She is/was; and how She is able to take my kinks and preferences and twist them and mold them into something that She enjoys as much as i do.

Without a doubt in my mind is Mistress Ayn of Atlanta www.mistressayn.com . She is incredibly creative both in the course of a "normal" session and Her 'mind fucks" - which truly need to be experienced to be believed! She is ALWAYS in control, that is just a natural part of Her personality. She is loads of fun. She is deviously creative!

Aslo, in my lists of "the best" are:
Domina Rikka (sadly, retired)
Goddess Samantha -http://www.fetishgoddesssamantha.com/
Goddess Phoneix http://www.goddessphoenix.com/

These Ladies are all creative and fun.