I am a size 6 for all my shoes and I ordered these in a six and they fit nicely.
There is just enough extra room to wear extra thick socks, or put in a comfort insole, to add some cushion, as none is provided.
Zips up the sides so you don't need to fuss with the string in the back to take on and off.
I have thin calves and there is some slack/space, even when string is tightened all the way.  However, I wear these boots with my jeans tucked in and it fits perfectly