A few took the "long way", but always ended up being delivered. Typically this happens around the holidays. The longest delivery time was about 3 weeks for an insured Priority Mail package which finally got moving and delivered after we filed a "lost package" claim. The USPS really does do a superb job with the volume they handle.
The seller sent all the USPS tracking info and the whole transaction was fine. The watch was supposed to be delivered Wednesday. My dad didn't get any mail at all Wednesday. He checked the tracking # online which showed the package delivered after the "recipient" had "signed" for it.