I just wish they lasted longer. My chair mats tend to last about 3-4 years and then they are cracking and I need a new mat. But it's better than having your carpeting (or your wood floor) ruined. Just be sure to get the mat made for your type of flooring.
It is perfectly satisfactory at present but the one it replaced (also from Staples) didn't last as long as it should have before developing rips and holes.
I've used this mat for 3 days and for me it works ok. I'm only 95 pounds and the chair does leave indentations which the chair automatically rolls back into. But the indentations aren't deep so I can still move around okay. I don't think it would work well for a heavier person. I have medium-pile carpet. I'd recommend a high-pile carpet mat for someone heavier.