Are Costco Diamonds Worth It?

Ever since I read that Costco was selling fine gems, including the stunner of a yellow diamond shown here, I wondered if the diamonds were of the same quality as diamonds sold in jewelry stores. ABC News must have been curious too since they took on the researcher. They visited both ends of the spectrum first picking up a diamond ring at Tiffany's and then one at Costco. The results? The Tiffany diamond cost more than it was appraised for but was deemed to be worth it for the "Tiffany experience" and the service and peace of mind factor. The Costco diamond was appraised at more than they paid for it and the jeweler indicated that he was impressed by the quality of the stone. So basically it comes down to perceived value, how much is  the little blue box from Tiffany and the smiling, attentive salesperson worth to you?