It's all about shape/looks for me and the services provided -- first. A lot of the time I don't find what I'm looking for. That's just part of the hobby IMHO.
It's rare that I repeat with someone that isn't a 9 or at least an 8 (to me) If I've seen a provider more than once it's either because she was very attractive or provided services other providers don't. Or both. Personality and even environment are often secondary to looks and services.
This is an interesting thread as I can see it being tough for providers to keep things straight in their heads when they get judged physically so blatantly. Lynn has made great comments and really has her head on right as a provider.
Anyways. My .02.