I've been using Go Run Ride 4's for quite a while (about 6 pairs over the past 18 months). They have gotten harder to find so I decided to change to the Ride 5's. I have no idea what the difference is supposed to be but there is no perceptible difference to me. They fit the first time I tried them on. I walked for 9 miles on the first time and only have positive things to say. They were comfortable and added a bounce to my steps. Love the color too. Been using them every day for about a week and am still feeling that I made a very good choice.