This is the chair mat I have been buying for years. It is heavy and awkward to carry so I have it delivered to my home. It gets a lot of heavy use - and it stands up pretty well. This is the only size mat that fits my desk so I plan to continue buying it.
The first day of use and the chair wheels have already broken the plastic. The mat is sitting on carpet so maybe it was the wrong one to buy though the previous one lasted a couple of years.