I see that most of the negative reviews come from men - for me the experience has been pleasant.
I joined in June. Yes, it's free - Truly free and I like the compatibility tests (although no one is required to complete them).
I have met 3 really nice guys - they have really good jobs and great personalities and although 1 was just "not for me" I have held on to the other 2 and REALLY like both of them!
True, there are some perverts and creeps on the site but aren't those types everywhere? Be sure to read all profiles before responding to messages and always trust your gut!
All in all, I like POF and suggest you give it a shot.
Oh AND I heard Patty Stanger (Millionaire Matchmaker) met her fiance on POF (she was on Steve Harvey recently - saw the interview myself)