I have high pile carpet and I'm not a small person....so the chair mat needed to be thick for both reasons. This one works well. Whatever denting I've put into it seems to disappear after an hour of not being used. The bigger size is useful too.
I bought this for my husband's office chair as he had worn a path down on the carpet pile and I had to shampoo it a lot! This mat works great for our office on 1/4" pile carpet easily with no slippage.