I've had this chair mat a few weeks and so far it is great. I can't speak to the longevity of it but it seems to be strong and well-made it provides good support for my chair over fairly thick shaggy carpet and it doesn't smell like petroleum. I hope it lasts a long time without cracking like my last one did.
As soon as I put my desk chair (5 point ball casters) on the mat divots were created. I could not easily move the chair. I didn't even sit in the chair yet! This does NOT work for medium to high pile carpet at all. The advertised use is completely bogus.