I didn't think there would be a difference between flat pile and low pile carpet for this chair mat but there is. My chair made big dents in the mat and wouldn't roll at all (I am a petit woman). My carpet is very low pile but not flat. Unfortunately Staples doesn't sell any other kind of chair mat with a lip in their stores.
When it was left on my porch it was draped across the box my chair came in. Took a couple days for the folds to completely disappear. Wheels of the chair don't seem to be leaving indents and I'm at the upper range of the chair's rating.
This mat is not strong enough to prevent a chair from quickly wearing grooves and dimples in it. These slowly worsen eventually causing the plastic to crack. It is good for a few months of full time use at most.
Thickness and quality of the material is below my expectation. Chair wheels quickly made dents in the surface so it is difficult to roll. Would not buy again.