I'm not a heel person, but I put these on at 3pm (for a wedding) and they didn't hurt until almost midnight after much dancing! Even then, there were no blisters, just ache from my feet normally wearing hiking shoes. I normally wear a 7, but they were out of stock and I bought the 7.5. With the backstraps pulled as tight as possible, they were perfect, so if you have to size up a half, or are in between, you will probably be ok a half-size up.
I love, love, love these and receive compliments every time I wear them. They are not the best for an all day shoe but are comfortable enough and didn't give me blisters even after a full day of walking around the city.