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.
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.