Ordered several of these for our office and everyone is having issues with the plastic being too "soft" and office chairs are making permanent indentations that the chair wheels then are getting stuck in as we try to move. I know they're one of the more reasonably priced mats but they aren't even worth the cost.
This is good for low pile carpet (3/8") but the cleats aren't deep/sharp enough to dig in to prevent some sliding. I have to re-center it under my desk after a couple of days.