I have been with 3 of the current lineup (Mako, Erika, and Yumika), but the last time I played was 3 years ago, so my opinion would probably be out of date. After a long time in the business, the girls tend to get less enthusiastic.
Anyway, what is "best" depends on your priority. If you get turned on by women who are slim to the point of being anorexic, I´d have to say Mako, hands down.