Wow - I have had arthritis all of my life and I'm in my 60's - so finding a pair of shoes which provide support, are attractive AND comfortable is nothing short of a miracle.  I bought an 8.5 in WW - I am normally an 8.5 W but the arthritis in my big toes is getting much worse and these felt like heaven when I slipped them on for the first time.  Plenty of room for warmer socks, and despite having an open back and a bit of room to spare, they do not flop around off the back of my heel.  And they seem warm.  I will definitely purchase at least another pair in another color - I cannot recall ever owning a pair of shoes so comfortable.