This mat is bigger than what you can find in the store and is a perfect size for what I needed. I'm glad I checked into Staples to see what they had. Perfect and of good quality.
Haven't had it very long. I am over 200lbs so I sink a little. I've rotated it occasionally. Hasn't slipped so the sinking was sort of expected for the price. It actually does help keep the chair in place ... and I easily "pop" out to roll. The spikes aren't anywhere near as deadly LOL as they were in the past. I'd give it 5 stars for the cost and quality if I didn't sink... but I think I probably would with a $100 one anyway.