Dan.com is a reputable service and was recently acquired by GoDaddy, the biggest player in the domain industry by a very long margin. They will act as an escrow

Dan.com is a reputable service and was recently acquired by GoDaddy, the biggest player in the domain industry by a very long margin. They will act as an escrow: take your money, get the domain into your hands, release the money to the seller. In this order. I think your only worry would be to buy the domain from its legitimate owner. Dan.com has it's own security checks on both the buyer and the seller for what it's worth.