I've worn more pairs of 574s than I can remember and most recently had to discard the now extinct 1320. Always had a size 12. They looked like a combination of both β firmer heel support and construction like the 574, but with a softer foam midsole like the 1320. Flat feet move a little inside the toe, even with the added orthotic. A deal breaker for me, however, is the sock-like construction. It tingles at the top front, at the entry point, feels like the top is tied very tight but the bottom is not, and it hasn't torn or loosened after weeks of wearing. They are light, soft and look good but my feet don't like them. I have to go back to shoes with a more traditional tongue construction.