Frist question, why does a girl have to perform anal to get a 10 rating? It seems to me, if its important to the reviewer, it would be factored in. Otherwise you penalizing some girls whether the service is wanted or not.

Secondly, Doesn't it seem the reviews tend to rate pretty high. I was looking at one reviews review, and almost every review was a 9 or 10. Doesn't "Once in a Life Time" mean onces in a live time, and lets face very few providers are really model material,

Ratings are only a guide ... read the reviews to find out whether you would give a similar score.

Some guys rate high.  To find that out look at how he rated a lady relative to her other ratings.  You can't tell if a guy is a high rater based on the ratings he alone has given   All of his ratings may be 9 and 10 because he does his research and only sees ladies that perform at that level.  

How exactly would one know that it was a once in a lifetime experience until one's life has ended?  By then it's too late to write a review.

Looks are in the eye of the beholder.  Fortunately many ladies do have photos so you can be the judge.

If you read the rating policy, a lady has to have 3 out of 5 attributes to be rated a 10. One of those is Anal. So, if she does not provide Grecian delights, she can have 3 out of the remaining 4 attributes.