I think there's an other topic on the same subject, or was, some weeks ago.
If I remember correctly the conclusion was that the price doesn't guarantee anything.
From my experience (which by numbers seems shorter than yours), my favourite is at 500 and it's because of her service and the GFE, plus she's quite hot.
I have tried an absolute beauty at 500 too, and my second or third best is just at 400 ...
Most of the classic ones will have many reviews, so you can check that. And then you just have a 500 girl which generaly offer great experience and that's a fair price.
The same way you just fall on a 500 girl, maybee not so well known, few or no reports, and she is just crap, whatever the reason (service often because it's what you can only judge afterward).
Personaly, I think this hobby is a bit about offering and receiving. If you want to save money there is internet porn
