A while back there was a thread where a few people asked if there is any fraud protection using a Postal Money order to pay for items.
I talked to an employee of the USPS for a few minutes today and he said yes, if you pay for something with a USPS money order, and the selling party either steals it, doesn't deliver etc, it is mail fraud, and to contact the local Post Master.
Then he kind of chuckled and said "The USPS has their ways", so I'm assuming there is a high probability that the merchandise or your money would be recovered.
Thought I'd pass this along, since I can't remember if it was discussed or not in the thread I can't find now.....