RE Free Super Saver Shipping w/ Amazon: how will I know if the shipment will come USPS vs UPS prior to checkout?

But they will post on the web site when they will do the expedited shipping for the free super saver shipping method during Christmas. They did this last year to make sure that items arrived in time. Most items shipping via Free SSS will ship through the USPS, but some heavy items will have to ship via UPS and you will only know this for sure after the order ships.

So yes, large heavy items will ship via UPS but most large heavy items aren't eligible for the SSS because of this. If you have questions before you buy, you can have them call you from their help pages. I hope this helps to answer your question.

The help pages also have a lot more details.