For those bashing the USPS, consider the fact that they handle about 1/3 of the total postal volume in the world. I think they do a pretty good job.
I get numerous packages via USPS every week. In fact it's the only package delivery service I use.
I've found their tracking information to be accurate. It sometimes lags actual movement by a day or so, but so what?
I use a little branch PO, and their tracking even distinguishes between arrival at the local sorting facility, at the main PO, and at the branch.