I've hit the second tier of rewards once, aside from that, it's mostly just accumulating money over a period of time. For someone who can't invest too heavily in anything else but this and mining, it's at least
something.Also, I think your account has to be at least a week old to get a payment? If you haven't gotten yours yet, try posting on the official thread. A simple google search will point you in the right direction. This is my first post so I can't put the link up, sorry.
The owner seems pretty active in his thread with many people confirming payouts, so I'm pretty sure it's legit, and any error is probably just standard computing/human error. I don't really see how this can be a fraud since you're not paying for much, just five minutes of your time.