One of my friends (a great dome) recruited and trained a large group of young and of mature women as subs or dommes and she ran a great service.  (She is retired and happily married now.) Another friend (a beautiful lady of color) was herself very imaginative and open to things (some of which I found behind the pale, but earned her a large following.)
I spent a few years about 7 or 8 years ago in NYC and that was of course loaded with both professional and amateur dommes and subs of both genders and included a number of TVs.  
The place I know the least but I bet is the very best in the country is of course San Francisco.  I have little experience there but have a number of friends who are free and for whom money is no object and they head there for BDSM visits.  They also favor Berlin and I must say when I was living in Europe so very very many years ago, I even then found Germans dommes and female subs to have an extra and extremely exciting touch.

NYC and Toronto hands down!!

NYC is the best 24 hour dungeons and Paddles the BDSM scene. Also Toronto- as an up and coming city.