There are lots of creeps on Model Mayhem. There are lots of creeps on Craigslist. There are great people with legit work posting ads on both sites. You can post ads on either site for free, so you're bound to find weirdos here and there. You just have to talk a lot with the photographer beforehand, use your judgment, and get references. At this point, there is no website for connecting models and photographers that allows user feedback on experiences.
The best way for her to find good people to work with is to make friends with other models and ask them if they know of good, legit photographers. Good photographers can also recommend other good photographers.
This is a small world, whatever city you're in, and word travels fast. The good people will generally know about each other.