I'm using the chair mats in my sewing room which has berber carpet. I'm hoping these will hold up better than ones I've purchased in the past. The old ones cracked and chunks broke out of them after just a few months of use. These are really smooth and easy to clean and chairs roll really nice on them.
I use this mat over a vinyl floor. It needs to be much thicker to provide a smooth rolling surface. I have a chair with 5 casters on it and they create divots on the mat. I weigh 200 pounds; so that distibuted over 5 casters should not create divots in a supposedly solid pad.