Agreed! I think paying vs free dating sites is like going to a thrift store vs a store such as Macy's. Sure, you may luck up in the thrift store, but it's likely you'll need to sift through lots of crap with a lower chance of success.
I used FB dating, although not with the apps. I just joined a bunch of groups and met some new people, went to some meet and greets, and made plnety of new friends. It's also good for making "friends" lol.
When I was on there, the quality of matches was generally better than other sites. Although I did meet one of my favorite exes on PoF. That site is very, very hit or miss though.