I like the size and shape of the mat but the material is so soft that the chair sinks in making it almost impossible to move (roll) the chair while seated in the chair.
I had recently bought the Martha Stewart simple desk and fabric chair and realized it was too hard to move the chair in order to sit at the desk. I also didn't want the chair to push permanent holes into my carpet. I was afraid I'd stub my toe on the mat but it lays perfectly flat and hasn't given me a problem at all. I had expected to have to put $40 to $50 into such a mat but it was less than $20! You can't beat that value and even though it isn't the highest quality available it works perfectly fine!