Few months ago I remember seeing how they were making some permanent changes in time for the holiday season, Priority mail would have specific delivery guarantees (not "ehh 2 or 3 or whatever days"), basic insurance, and tracking automatically included. Specifically to compete against Fedex/UPS.
Just shipped out 3 packages via Flat Rate Priority. The 2 in-state (Michigan) were 3-Day, and the one to Spokane, WA was 2-Day. Both arrived in the 2-Day timeframe though. Tracking was superb, also:
December 16, 2013 , 4:01 pm
Delivered
HOUGHTON, MI 49931
December 16, 2013 , 8:39 am
Out for Delivery
HOUGHTON, MI 49931
December 16, 2013 , 8:29 am
Sorting Complete
HOUGHTON, MI 49931
December 16, 2013 , 5:34 am
Arrival at Post Office
HOUGHTON, MI 49931
December 15, 2013
Depart USPS Sort Facility
KINGSFORD, MI 49802
December 15, 2013 , 12:35 am
Processed through USPS Sort Facility
KINGSFORD, MI 49802
December 14, 2013
Depart USPS Sort Facility
OAK CREEK, WI 53154
December 14, 2013 , 5:21 pm
Processed through USPS Sort Facility
OAK CREEK, WI 53154
December 14, 2013
Depart USPS Sort Facility
ALLEN PARK, MI 48101
December 13, 2013 , 2:26 pm
Processed at USPS Origin Sort Facility
ALLEN PARK, MI 48101
December 12, 2013 , 6:36 pm
Acceptance
LIVONIA, MI 48152
December 12, 2013
Electronic Shipping Info Received
Edit: OP, have seen stuff like that before though. USPS got really confused this summer when I had company send me two packages on accident, same tracking number.