In my short time on this site, this subject has been beaten to death and then some.  My take on it - reviews are what you make of them.  

As they say, beauty is in the eye of the beholder.  Maybe to a number of guys who really don't see many ladies, they rate a 10 for appearance.  I've seen a number of women who in my opinion are between 7-9.  You may rate them differently.

As far as the other rating scale, it is also subjective.  Maybe the person experiencing something new/different? He may be using his prior experience in his normal area to compare and he believes the experience warranted the rating.  

At the end of the process, every person has to make a determination of what they believe is appropriate.  I don't try and understand it.  I'll make up my own mind whether she's someone I want to meet or not.

As previously mentioned, the ratings are totally subjective.  Many experienced mongers will, and have in various forums, say they take the numbers with a grain of salt, and place more importance on the text of the review.  Read the review, don't worry about the numbers.

LLAP,
Swim