The thing is, you almost have to offer USPS to keep the actual cost of goods to the customer down. Most people, if they are shopping for something, look at what it costs them for delivery and factor that in.
Overall, the USPS is actually pretty good, though when something gets "lost" it can be really aggravating. Especially if it's a couple of boxes of things going to Italy:-) Aside from the two boxes, though, I'll bet I end up with 1:1000 that doesn't get delivered, maybe less, and 1:250 that has some kind of problem, mostly being really late. Whatever they say for international delivery I always add two days to it.
If Wayne's system works like mine, the delivery confirmation number is created by me, and I don't think I've ever seen a message that it got into their system until it was delivered. Except for media mail/parcel post, then delivery confirm does work as a tracking number. You can use it for first class, too, they say that the envelope/box needs to be 3/4" or thicker. I use it all the time on thinner envelopes than that, and it works.
On the whole, I'm really happy with them.