I don't, but I know a lot of people who do. Before you buy them, you must know this: They are NOT meant to be worn as usual running shoes. They are meant to be used as strengthening tools, and as such should not be used for the majority of your runs. I believe Nike recommends that you wear them only for a few miles per week. It is possible to work up to higher mileage in the Frees, but it takes a while, just like running barefoot. People are so used to the cushioning and support offered by regular trainers that they have to retrain their bodies to run without that stuff. Your stride shortens, you absord the impact with your knees more, and you land on the ball of your foot rather than the heel. It takes a while to change to the new form.