This is the third pair of these shoes that I have purchased. I went initially to a running store to be properly sized and "shoed" for running. However, these shoes are typically $150, so I always look for cheaper prices online. These are a great shoe for me. But - I always recommend that you are properly fitted by a professional. The new shoe (this is the 6th edition) is slightly different from the 5th edition, yet is still a great fit and I hardly notice a difference (these may be a tad lighter). For those buying their first pair, I recommend at least 1/2 size up - as they run small (and your feet swell when you run).