For a long time I resisted buying into the hype of toning shoes. In fact, I did not purchase the shoe in hopes of magically losing weight or toning up. I bought them to get a comfortable shoe, and after reading many reviews, on many different brands/styles, I decided to take the plunge. When you first put them on and walk around, yeah they feel strange like you might fall from trying to balance on them. Yes, you do feel like you are walking on a rubber ball in the middle of your foot. I have very bad bunions on both feet, and one flat foot, which makes it very difficult to find comfortable shoes. I need shoes with arch support to prevent pain in my feet. These shoes are the most comfortable shoes I have EVER worn. The instructions with the shape ups tell you to wear for short periods until you get used to them. I wore them all day without any problems. I don't know how they would be on uneven terrain, as I wore them on flat surfaces. I also recommend ordering 1/2 size up, as I ordered a different style from Amazon of shape-ups in my normal size, and had to return because they were too small, so I ordered these 1/2 size up and they are perfect. They slide some on the heel, but I have a narrow heel anyway, and I just tie them tight and they are fine. They are more stylish than other shape-ups, and looks more like a regular athletic shoe, not as "clunky" as some styles. As to whether or not they actually tone, that I will find out in time. I highly recommend this shoe,especially to those individuals who spend a lot of time on their feet. Your feet will love you for it. :-)