I usually wear 12 depending on the shoe and I probably should have ordered 11 1/2 but they are great for what I do. I work in the IT department of a hospital, so I'm on my feet a lot, going under tables and moving computers and equipment. The shoes are very comfortable and have good flexibility. They seem to scratch fairly easily, but I just need to polish them. They tend to get hot when wearing thicker socks. When I wear my black long Hanes socks they get very hot, but when I wear thinner socks it becomes perfect. They never slip. I've used them in the car and at work and haven't slipped on the ICE or anything. But because of this, they pick up each brick and tape you in place, so remember to tap/stomp/wipe your feet when you head to the garage or to work. If I was rich I would buy 10 pairs in case they stop making them. The memory foam is fantastic and high quality. Feels new every time I put my feet down.