I started out looking for Wellies to slip on for quick trips to the store in the rain, shoveling snow off the steps in winter, etc., and just happened to see these Bogs. I take a size 8.5 shoe and ordered a 9 so I could wear a heavier sock and the fit is perfect with medium weight rag socks. I've worn them a few times for an hour or so out in temps in the high 20's to low 30's and found them to be pretty warm. Since they are rubber, if your feet perspire and you plan to wear this for an extended period of time, I would consider socks that wick. The green collar/insert is stretchy so aids in keeping them from slipping if your feet are medium to narrow. I'm not sure how comfy they would be if your feet are wide. The heel fits nice and tight. The rubber is an odd color that, depending on how light hits it, is either dark blue or dark green. All in all, I am very happy with my new Bogs and highly recommend them.