I have both the v3 and v4 and they both have their pros. The v3 to me just feel more plush and a bit wider on the toe box that may be since I have used them longer but immediately felt like the perfect walking shoe very plush. When I got the v4 they felt slightly slimmer and more of an athletic shoe that I could run in. The v3 to me is not a good running shoe at all but the perfect all day walking shoe.
