I purchased two of these chairmats for a home office. They work so well and it's nice to know that the new carpet won't be damaged by rolling office chairs. Only con was the strong plastic smell when I first purchased them.
This is good for low pile carpet. Do not use for higher thickness carpet. The Mat will crack in time if you do. Otherwise it is a great protection for your carpet.
I have a wool hooked rug under my desk and the desk chair would not roll very easily which was frustrating - who wants to get up off their chair to move it when you're busy on the computer? This mat is perfect! The chair rolls easily the grippers on the mat keep it in place ALWAYS (but hasn't damaged the rug at all!) it's clear so you can still see the rug design underneath the mat and it's heavy enough that the mat does not bunch up or crinkle. Also appears that it will last a long long time. :)
About a week after I made the purchase Staples published a "10% off any purchase" coupon in one of their advertisements. Had I waited I could have saved myself a few dollars.