In my experience..
I find that the very high end, 10's are usually not very nice to me! Since I make sure that I am well dressed, clean,shaved,smell good (before any appointment) and I'm not that bad to look at I've come to the conclusion that they are not nice to anyone because they don't feel they have to be! There have been a couple exceptions..
I find that girls that are say a 5/6/7 go the extra mile sometimes, and believe me, make up for thier looks in service.
I have also met some surprisingly good looking girls in the Franklin strip area, with relativley no attitude, but with more safety measures in place. I have never had a good experience from any of the girls on the high track, unless I have seen them on low before hand, and there aren't many that make the switch.
So...I would have to agree with deke
A very good question/observation, squid!