Oh, I don't know. A couple of years ago I needed to send a letter to Europe and it had to be there in a couple of days. Hearing all the bad stuff about USPS, I decided to use UPS (don't ask me why - I won't do it again). Three weeks later the letter arrived. Oh sure, I got my money back for the freight, but the whole point with next day delivery was kinda lost.

My point is that if you look at just a few instances, you can always find good or bad experiences. But in this case, UPS will never get the chance to show that they can deliver, just as USPS won't get the opportunity with the original poster.