I recently ordered a book that was shipped by USPS. I followed the tracking on-line and it was a bit amusing to see the journey. That book got a very extensive tour of the east coast before it made its way to me but I did eventually get it.
I have to say that the USPS chain (or any other carrier) is only as strong as it's weakest link. Every time the package is sorted it must be correctly routed or the entire process is compromised. I'm not sure any carrier really shines so price is the important factor to me.