I haven't worn any athletic shoe brand other than Nike Air for working out in years,so I was skeptical when purchasing these Reeboks. However, I did my homework and watched a promotional video on the shoes and was amazed at how flexible and lightweight they looked. Plus the bottom sole of the shoe is seperated into several rectangular pods that make the sole extremely flexible. So I decided to give them a try. I ordered them in 10.5, the same as I wear in Nike brand. I was concerned because some other brands fit differently, such as Sketcher and Puma which run big on me. They fit perfectly. They did alter my stride a little when I ran on the treadmill with them. Reebok claims they encourage a more natural running style that minimizes impact and mimics barefoot running. Overall I am very pleased.