Its really subjective. For example, for my very first SP visit I saw a really well reviewed lady (with 7.5-8 rating for looks) but when I saw her I was severely disappointed. Other ladies on the other hand, with a bit of a lower rating looked really good.
Candlelight: I suggest you to book a session with Karissa and then do go ahead with the session only if you are satisfied with her looks. Its hard to walk away but you gotta do what you gotta do.