I have the boot covers and don't like them. When I used them I did not notice that the kept my feet any warmer, but you do have to be very careful when moving on your stand. They have a "non-skid" type botton and are loud if you don't "lift" and "replace" your foot.
That said, I have had guys tell me that they work well by taking off your hunting boots and only wearing the Artic Shields once you get on stand.