I absolutely LOVE these boots! These are my first pair of Cole Haan's and I have to say they live up to its name.  I have been on the "hunt" for a comfortable, classy, all-around boot.  I have finally found it.  It took me a couple of tries, in having to return them to get the right size but Amazon was great in working me to get what I needed.
For me, the boot was accurate to one's true size.  I wear a size 8, which is what I initially ordered, but because of the added Nike support inside the shoe, the fit was a little "tight" for me.  I also have a high instep so that was an added concern with the original size.  I returned the boot for a 1/2 size larger (8.5) and they were PERFECT.  The comfort, arch room met my needs.
I will say that I tend to wear boot socks and that helped to minimize on slippage around the heel area. Without the socks I could feel some slippage, but nothing too bothersome.
Additionally, I have small calves (<13") and small ankles.  I have always struggled to fit a boot that fit right all the way through.  Also with boots that zip up, I tend to have the zipper cave in toward my small ankles creating some discomfort.  So finding these boots w/o a zipper yet with adequate pull-on comfort that holds its shape was a biggy!!  I was concerned at first, if the boot would fit "baggy" because of the semi-suede material on the back side.  However, to my delight, they fit my calves very nicely wearing skinny jeans or tights and a skirt!  So for all the ladies with small calves, these boots weren't an issue!
I am so satisfied and happy to have this brand in my collection.  I would HIGHLY recommend these boots to everyone!