USPCC moved its manufacturing from Ohio to Kentucky and started up a new manufacturing line using new presses and cutters. To me the card edges seem rougher and develop a click bend easier, but that could just be my imagination. Also, that may just be a result of them working out the kinks in the manufacturing process. Nonetheless, after I've broken in the cards, I can't tell the difference.
For a while, the pips on the cards were slightly smaller (with the pips on the index being slightly larger (you can tell these decks because there is a white border around the advertising cards. I had e-mailed USPCC and they responded by saying that they were changing back to old sized pips.
I don't like the new boxes, but fortunately I still have at least 50 unopened Rider Backs.