The time it takes for UPS SurePost to deliver the package is between 1 to 2 days longer than UPS Ground Shipments.
So your package may take 4 to 5 days to reach your post office or address where it would normally take 3 days to have UPS ground deliver the package to you directly.
However weekends and Holidays can extend those delivery times.
UPS SurePost is always delivered by the USPS to your post office box or to your home address.
The UPS picks up the package from the sender and then takes the package on the UPS trucks or planes until it gets to your state.
Then when the UPS gets the package to your destination then they will take the package to either your local post office or a USPS sorting facility closest to you where the USPS will then do the final delivery of the package.
On UPS you'll have a UPS tracking number and to the right of the screen on a desktop computer or laptop you should see a USPS tracking number.
The USPS tracking number can then be used to track the package when it gets handed over to the USPS.
UPS SurePost is much better than FedEx Smartpost and I've had no trouble with UPS SurePost.
The UPS SurePost is only a day slower than UPS ground delivery which is not a big deal to me.