These shoes are exactly what I've come to expect from Mizuno and why I always come back. Like always, I was able to go right out and run in them without any blisters or discomfort (basically, they don't require any breaking in.) I have a wider foot and somewhat high arches, so I have been wary of more recent Wave Riders due to reviews that they run small/narrow. I did not find that to be the case at all. I am usually between a 9 and 9.5, and the 9.5 fits absolutely perfectly. These shoes have more support than my last pair (Precisions) but feel just as light and roomy in the toe. Extremely happy with the purchase (and the colors are pretty great too!)