I had these under all my games at my apartment and they were EXCELLENT. However, for whatever reason, they are total crap on the carpet in my new house. The carpet here is a bit shaggier than the other stuff, dunno if that's the difference or not. At my apartment I could move a game by myself, rotate it, slide it into place, etc easy peasy. At my new house it's a choooore. It's like they're not even there.
Eventually I'm going to redo the flooring in the gameroom, which means that carpet is going. Until then, I'll just live with it.