I have what I was told os medium pile carpet.I have an office chair purchased at Staples a year or so ago. The mat slips and every few days I push it off yhe mat so I can move the mat back in place and not curling against my desk leg.and then placing this heavy chair back on the mat. I also have depressions on the mat from the casters. the mat shifts I suppose because of movement of the chair.
The mat itself I will give a 5 star rating. It was rolled when I picked it up but the salesman (Evan) assured me it would flatten overnight. And it did. My reason for a 4 star rating is the tape that was used to keep it rolled. It did not remove easily and left a very sticky residue along the entire tape line. I will try rubbing alcohol or Goo Be Gone. I’m sure either of those will work perfectly but just annoying it has to be done. Use twine or a different tape. I would recommend the mat but would share the post sticky residue removal process.