The sole fit well, but the heel strap is too tight.  The velcro fastening doesn't allow much variation on how tightly or loosely you can adjust it.  The result is that the toe divider is crammed farther between the toes than is comfortable, and rubs against the bones, creating blisters.  For context, I do also wear flip flops--not one of those who can't stand anything between my toes--but this is painful.  I had really high hopes for these working out well, since the area I like running that is closest to home has a lot of blackberry thorns and gravel which makes it unsuitable for my bare feet, at this point.