I made an order through them tonight. I was worried too, so I made the order through "Clearcoin," which is a bitcoin escrow service (created by the founders of bitcoin from my understanding). So, one way to know to know it is not a scam is to use an escrow service (always a good policy, actually).

How does any skeptical person know that it's not a scam? Give it time and see if/that other people use it successfully.