I use this product at my computer desk on a carpeted floor. The mat's spikes prevent it from slipping and moving on the carpet when my chair on rollers slides on it. The clear color allows the carpet to be visible underneath. I bought this mat to replace a similar one that had multiple cracks. I am hoping that this one lasts well.
Currently have mat on top of carpet. Chair's rollers tend to sink into the mat quickly so rolling can be difficult. It does protect the carpet (which was the goal). That said I'll probably invest in something a little better/thicker next time around.