I bought a pair of old Go Run 600 shoes and really liked them. I ended up buying 2 pairs of these newer ones and for a much lower price (originally paid around $40). These running shoes are comfortable, light and very comfortable. Note, however, that the sole of the shoe has almost no traction. The difference in size between 11.5 and 12 is actually quite noticeable. I wear size 12 shoes (Nike and Saucony) and they are a bit large. I've taken a few internationally and go for a run (no pun intended) at least 3 times a week. The bottom of the boots hasn't changed from a lot of friction. Overall, I am very satisfied with these sneakers and can only recommend them!