I don't have the Mag...I have the Flash (my guess is the same sizing). Sizing is pretty dead on and similar to my Specialized BG's. Upside is they're unbelievably stiff. Downside...the material isn't very comfy, they can get pretty hot in the summer and the top strap doesn't allow for it to close enough (the strap hits the buckle) thus they're about 2 clicks too loose at the top of the tongue. I generally only ride them in the winter when I have thicker socks or it's not as hot outside.