I don't think this mat is a good quality because it's kind of thin and will not hold heavy weight. I'm keeping it because I bought this for my 9 years old son.
Chair mat is too thin to be effective. Leaving chair on the mat overnight resulted in dimples where the chair's wheels were. Might be fine for low pile office-type carpeting but I'm using in home office with household carpet and it just sinks down too much. I cut 2 ply cardboard to same size as mat to place underneath and that seems to help but it's not very attractive.
I have an odd shaped desk. This worked perfectly with a small modification made with some strong scissors. Great to buy from the store and get it set at my desk the same day.