It works. However, Adult Friend Finder is especially good for taboo relationships, i.e. swinging, younger/older, etc. If you're searching for a good long-term relationship, from my experience, Adult Friend Finder isn't so great. When single, I tabbed around a bit, using AFF, using the site with no intentions, but with excellent results. I'd make sure you use a picture, if you sign up, because most of the worthwhile ladies won't meet without one.
It is OK, but don't exect spectacular results. YOu have to have a picture of your face and your penis if you want to get ANYWHERE on it. However, I've fucked two girls I met there.