It depends on why you're asking. There's SAAFE which is a sex worker forum, including a dodgy punter section, and Ugly Mugs which they use to report dodgy, dangerous punters.
They have no site to rate us. Why would they, the ratings would be paid / didn't pay, was decent/ was an arse, etc. Be a decent punter and there's little to worry about.
As others have said, it's generally the ones who've merited negative reviews who object, so no loss. For the good ones providing a good service, there's rarely a problem in my experience.