Better than no chair mat but a bit thin unless your carpet is the short/firm office type pile. Our carpet is a little plush and the mat develops dents if I leave the chair in one place for too long.
The mat would be great for someone who doesn't weigh much and isn't using a heavy-duty office chair. My husband(weighs about 180 lbs + chair weight) tried it for two days and the mat was starting to get dents in the parts where the chair wheels were so over time it would just be a hassle to move the chair out of those dents in the mat.
Cons: - Does not stay put on my carpet - constantly has to be moved back into place - Huge indentations from my office chair in the mat constantly Pros: - Cheap
I really shopped around for size and price and settled on this combination. It is fine but remember that the chair casters of anyone over 100 and some pounds will make indents in the plastic. I knew this and can live with it. To get a thicker mat costs a lot more money.