I'm in another country, so maybe my issues are related mostly to international shipping, but I've had the following in the last month with USPS...
* No tracking - the item has the electronic info registered and then nothing until it shows at my door.
* Stalled tracking - the item is tracked to a location and then the tracking doesn't update until it's out for delivery.
* Unavailable - this is intermittent; packages pop in and out of online tracking. The same package can wink in and out of existence several times.
* Black Hole - some packages go to a location and sit there for weeks (not in customs, just in some random location).
* Bizarro routing - I had a package sent from Seattle (200 kms from me) that got sent to Israel (you read that right) and then to me.
Soooo... yeah, I'd say USPS is pretty taxed at the moment. Doesn't help you in your hour of need, of course, but I can also say that everything eventually got to me.