Really seems to depend on your city/area I know 'plenty of fish' and 'match' attract a lot of creepy types in my area but on here they are often spoken of well.
I found rsvp best for me as a rule, sites you pay for attract a more serious crowd serious about meeting someone that is :)
How you write your profile has a huge impact on who you attract as well so get a lot of friends to help you and maybe even a few of us on here to check it out before you start.
Good luck it's scary but a huge amount of fun, as long as you are strong, happy and centred.You need to be prepared for knock backs and let downs, it can be emotionally draining and mentally exhausting ! But hey it works for a lot of people, it's a game don't expect to jump on and everything fall into place in a few days, give yourself time to learn how to play, be patient