It has been in place only a few days but I find mat dimples just with the unburdened weight of a wood desk chair. Mat is workable but I believe mat of soft material. Mat sits on very low pile Berber rug.
I purchased this to go on top of the carpet in my office and it does work but it is thin. I would go for the next one up if I were to purchase one again.
When you chair stays in one place for any length of time it creates grooves where the wheels are. So it's just as hard to get out of those groves as it is rolling your chair along the carpet that the mat is on top of.