I haven't read the thread all the way through, but will put in my vote for USPS Priority Small Flat-Rate Box. When shipping or receiving knives whose price-points start around a hundred bucks and go up to a grand, the 7 dollars is pretty cheap and the service "in my area" is good. (I too think the phrase in quotes is key.) I don't get home delivery as my private dirt road would require an RFD box six houses away on the paved street. The PO box is secure even though the window hours are somewhat restrictive and the lines sometimes long and slow.
Adding to the standard $50 insurance for Priority Flat-Rate is 3 or 4 bucks and includes free signature confirmation. The tracking is excellent and 3 business days is about the longest I've waited. We did have some issues at my PO with packages "returned as undeliverable" when they started using scanners, but they've squared that away pretty well now.
I get a lot of stuff (not knives) through Amazon Prime and use a four-line address with my street on the second and my PO box on the third. That way, UPS can deliver to the house and USPS to the PO box depending on how it's shipped to satisfy the 2-day delivery benefit that comes with Prime. If I'm worried the vendor will enter the address incorrectly, I just go with the PO box as it's surer. I'd rather wait an extra day or two than go through the hassle of a package returned to sender if the address doesn't scan.
I never ship out UPS unless forced to as it's more expensive and much slower. On the other hand, I've had pretty good luck with UPS delivery to our house as our local drivers are excellent and stuff generally arrives in good shape.