We have gone through a couple of different chair mat types that didn't meet our needs primarily because they didn't properly support the chair wheels leaving very deep indentations in the mat. This mat is significantly thicker and does a better job. There are still light dimples where the chair wheels have been but they seem to relax and reform after a while when the chair is moved. Low plastic odor compared to some others.
Three stars because the mat is softer than anticipated. I've never seen a flexible chair mat. I ordered medium weight but thought that just meant a little lower quality/not for heavy use. The mat is flexible and the wheels of my chair make indents so still a challenge to roll. The price is good. It doesn't shift on the carpet.