I don't think it's a scam, though I did thought so at first.
2 days ago I started mining for 16 hours with ~330Mah/s and it shows I need to get paid for 2.1 PPC when confirmed, I immediatly switched to coinotron, but I just entered my profile and it shows that half of my shares are accounted for (some still waits confirmations) and my balance is 5.33790279 PPC..

So I don't know, maybe the estimated PPC is wayyy off, but it does eventually gives you the coins at the end?