Vionic really seems to have trouble with consistent sizing, and these sandals are no exception. I'm usually an 8 in pretty much anything without socks, and I'm an 8 in Vionic's&nbsp;<a data-hook="product-link-linked" class="a-link-normal" href="/Vionic-with-Orthaheel-Technology-Women-s-Caballo-Flat-7-5-B-M-US-Black-Suede/dp/B01MR7ITYR/ref=cm_cr_arp_d_rvw_txt?ie=UTF8">Vionic with Orthaheel Technology Women's Caballo Flat (7.5 B(M) US, Black Suede)</a>, but an 8.5 in the same shoe in a different color. This shoe fits the sole of my foot and the straps seem about right, but the arch starts further toward the back of the shoe than any other pair of Vionics I've worn. If I scoot my foot toward the back of the shoe, it sits okay - but the shape of heel and toe bed seem to want my foot further forward. I end up sliding forward again as I walk, which makes the arch support really uncomfortable.

I also find the leather feels stiff and kind of cheap, more like a $30 shoe than my more expensive brands. The shape of the shoe also made me feel like I was clopping like a Clydesdale, rather than walking smoothly. Overall, this one is a loser for me.

If you're in love with this style, I suggest ordering two or three sizes and seeing which fits best. But the price seems to fluctuate a lot, so keep that in mind when ordering.