I learned a long time ago that USPS tracking was next to useless. Almost everything I ever got via USPS I would get before the tracking said anything other than electronic shipping notice received. I've actually been kinda surprised that most of my shipments from V4L have actually had regular updates on the USPS tracking. That being said, don't give up hope, even though it says nothing other than shipping notice received, odds are it's almost to you.
Hell, even though USPS delivered my package to the wrong mailbox yesterday, I still prefer them over UPS or Fedex (but that's partially because I can't receive UPS or Fedex where I live, so I'd have to go pick up anything shipped
through them from their local center, or have it delivered to my mother's house)
And priority mail is still faster than UPS ground, unless it gets misrouted, and I've had UPS misrouted at least as often as I've had USPS misrouted.