UPS actually delivered some lenses to my doorstep in pristine condition, box and all. That was the first time I ordered online (via KEH). I do believe that it's not the courier's fault, but maybe the shipper's, unless something really bad happened along the way (force de majeur).
For non-North America buyers, USPS is probably the slowest among the usual suspects (FedEx, UPS, and USPS), more so here in the Philippines where our local post office does a horrible job with packages. There's a good chance your package might get tampered in a not-so-nice manner, if not lost, along the way.