It's unfortunate that these shoes don't come in two widths, medium and some kind of wide, as otherwise they'd be perfect.  As it was, however, they didn't fit my wife and I had to return them.  My own feet run wide, but my own pair of Vivobarefoot shoes fits me perfectly.  However, we've seen the same thing with Vibrams.  When we buy regular shoes, like New Balance, we both buy the same width of shoe; but the Vibrams and Vivo shoes fit me, and are too tight on her.  One-width shoes for women seem to be designed with a narrower "default" width for women than they do for men (maybe a medium to wide for women, and a wide to extra-wide for men or some such), and that seems to hold true even when they're special shoes like these, designed to give more room and movement.

As a result, this shoe -- which should have been in my wife's size -- felt tight across the widest part of her foot, causing her some discomfort when she walked, and defeating the whole purpose of the shoe.  Once again, women with wider feet are sold short by a range of one-width shoes.  It shouldn't be a surprise, but in this case, it's particularly disappointing.