Given that I have had hundreds if not a thousand packages shipped to and from the USA using the USPS, and had a grand total of zero lost, I am actually shocked at how competent they are. It's absolutely incredible that they could manage a 100% success rate over a sample size that large. I mean, knock on wood, because for all I know the skis that are en route to me will now disappear, but imo they're very, very good.
UPS, I will never use, because they are liars and thieves. Charging the shipper for postage and the recipient for brokerage (usually twice again the postage) is extortion. Fuck UPS.