This boot needs a zipper in my opinion.  Due to it not having one, the top of the boot is extra large and allows for your foot/heel to easily slide in and out while walking.  I typically wear a 6.5 and it fit true to size.  Perhaps if you have larger ankles the boot won't slip, but it felt uncomfortable to me.  Also, with such a large opening it would have looked a bit sloppy if you wore them with a skirt or with jeans tucked in.  Watch the Zappos video and you can see what I mean.  Sorry, but I didn't keep the shoes.