Yes, I've tried them, and I wouldn't recommend them. They are stiff, rectangles that are strapped to your foot, so you can't just put the ball of your foot or heel on them. They also have a texture, kind of like "scales", under the forefoot, which is used for brakes. It makes it difficult to do anythying but a forward skating move.
(I'd highly recommend Gliding Discs over these any day).
HTH!