It is a good quality mat but it does dimple from the weight of the chair and me when at my computer. Next time I will go for the hard surface mat even though it is more expensive than my chair which I bought at staples.
This mat is a nice mat but it is certainly not designed for a thick plush carpet like it is marketed for. The nibs on the bottom of the mat are simplly too short to grip the carpeting and it moves around with the chair. This was the second one I ordered because the first one was even worse. Perfect opportunity for a new entrapreneur to enter the market and do it properly. I would not recommend this to a friend who has plush carpeting.
This mat is much thicker than my previous mat. Should hold up much longer. I was concerned about the "lip" but it is not as pronounced as I had expected. I like the extrusions on the bottom which hold the mat in place; they are less sharp than my old mat. My chair rolls well on the mat. I am very satisfied.