Are you talking about a single review or the consensus of many reviews of a single girl? In my experience, when a girl has several pages of reviews that are consistently good and similar, I have found them to be very accurate - like 90%. Assessment of a girl's face can vary quite a bit just because everyone can have varied taste on what is or is not beautiful. However, the descriptions of service have been very accurate.
I think part of it is that I am from the USA and here there is not the huge number of agency escorts. There is a website that offers a healthy review community of backpage girls but those girls have huge turnover. I have said before that you guys in Montreal dont realize how lucky you are and mostly that refers to the hot girls, the great agencies and the low prices, but the other thing is this forum and the really big community of people who write detailed, helpful reviews.