Lots of BP-bashers on here - but most of the ladies that are active here have and/or continue to advertise on BP from time to time. My opinion of the bashers are that they are either ladies on here that want to keep the lower end/cheaper girls down, guys that have had bad experiences on BP or guys that are too lazy/too much money to put in the work.

There are definitely fakes - some pointers below - but the rest are legit in my experience. There is a big range - from the streetwalker hood rats to the MILFs to the inter state transients to the genuine gems.  

Research, research, research

A couple of pointers

1 - if it looks too good to be true, it probably is. Professional grade photos of supermodel girls - fake.
2 - Google the numbers - if they show up consistently with same pictures, maybe legit. If the pix seem to change frequently and are very good looking - see #1 above
3 - checkout TER. If Google gets a hit on the number and a TER review shows up, check it out. Look for consistency and who the reviewers are. A single high review from a reviewer with only 1 review - probably fake. Lots of similar reviews - good or bad - from reputable reviewers will give you a better idea what to expect.
4 - use tineye to get a hit on the photo - lots of girls clip photos from websites. While it is possible that you will see a model/pornstar/NFL cheerleader on BP - odds are not likely
5 - ask on this board if anyone has seen the girl. However, better have done all steps above or expect to be flamed.

 
Happy hunting