As far as material, there have only been minor changes with the newest Decks. They corrected all of the errors that were present with the latest edition, but these errors/corrections can be found on the Decks website also.
In terms of construction, the new decks are on much better paper, and the cards are color coded in light colors. For example, the Micro/Path cards are printed on grey cardstock, while the Dental Anatomy are printed on a light blue. The font has also changed.