I have several sites, FC is actually one of my newest and the only one in the GPT area I haven't received payment from yet (Not to say they're a scam, just only been a member about 30 days and have to wait for the cash from last month to arrive).
I'm also active in three very good human intelligence task sites and once you're established and earn a reputation from the vendors for quality material, especially if you can write quickly and well, on some of those you can make a large amount of money daily or weekly within a few months if you put some effort into it. And yes, they pay.
Those PTC sites are hit and miss. I have 3 I will use and refer people to that pay on time every time, the rest I avoid. (As a rule I never refer anyone to a site until and unless I've had at least 3 cashouts that go off without a hitch, if I'm not getting paid how can I tell others to join and they'll get paid?) Very skeptical about those in general.
And I've cashed out 5 different survey sites already this month. Three of the payments already arrived, plus a bonus check. Cha-ching!
FC is a good site, it has some unique features and is a good way to supplement a little. But if as some have posted here and there you want to make more then grab the bull by the horns, do the research and go out and get it! Nothing wrong with adding to your repertoire if you have the time and need the cash, and yes there are other trustworthy sites out there. It's not disloyal to have multiple income streams, honest.