I had a pair of these from maybe 4 years ago.  Used heavily, they were getting a little worn out around the fur rim (not a knock for 4 years that's pretty good).
The new ones have slightly different yet softer fur!!  Such a great surprise.  I can also very easily slide these on (if my foot is at the right angle) without having to touch em.  Bonus!  I'll keep the old ones for going to the mailbox or something.  These babies are keeping me warm indoors!