I love my SIDI's, although the insole is crap and should be replaced when you get it. Besides that, it fits my feet extremely well and I think it does an outstanding job of keeping my feet cool in the summer. It will however keep your feet frigid in the winter. Also, their non-carbon hybrid sole (on the Genius models) save you money while still remaining light and stiff. I do know that some people have problems with the shoes because they have wide feet. I have narrow feet so that is not a problem, but if you are looking into SIDI's, they make a "mega" version for wider feet.