my wife is a US Postmaster. Every time I ship guitar gear, she reminds me of the different types/methods of shipping... With them, "Priority Mail" means 2-3 days, air shipped, and "better handling." Parcel post means ground shipped. I shipped my Mesa TA15 from Cincinnati to Louisiana and it was $40 PP and $50 Priority. I shipped priority. Yesterday, I shipped my 2 Channel H from Cinci to Seattle. Much bigger box, much heavier. The buyer said he had an account with FedEx and they would be the cheapest way. Sure enough, $50 insured. I'm sure as soon as I say this that someone will come in with a horror story about shipping with the post office, but it's proven that their track record is far better than FedEx or UPS, and this includes both shipping methods. She said if you use priority mail, the chance of damage is a fraction of what FedEx or UPS is. Costs a few bucks more, but I do it almost every time. A few years ago, before they quit doing it, I was shipping big gear (Mesa Lone Star combo, and Rivera Fandago 2x12 combo!) to South Africa to a friend. We could track it all the way til it hit S.A. and he had a friend at Customs so he'd hit them up as soon as it got there. Those two amps, several guitars, multiple pedals... we never had one issue. He said the issue would be on his end as Customs was a bit crooked and guys see "Mesa/Boogie" on a box and that box would disappear from Customs. LOL But his friend there would look out for his stuff as soon as it hit.
Nobody is perfect, but this is only the second time I've shipped anything big and not used the USPS.