The USPS are indeed dreadful. Cheap, but dreadful.
I have been culling down my rare music stash, and most of it goes overseas since this is where all the high rollers are these days, and I always use registered air mail. Speak to 5 different clerks and they will tell you 5 different things on their policies. Go to UPS or Fedex and their policies are set in stone, but they charge an arm and a leg.