From what I have been told by my dealers service manager, the front differential is on its third design (two revisions and the original). The advantage of getting the new one, being assured it is the latest revision might mean that you will have a more dependable unit. Getting a used differential, there is no guarantee. If you can get a used one cheap enough, lets say 1/3 price of new, go used. If over 1/2 price of new, I would go new.