Store employee was quite helpful in finding me what I was looking for. I have no complaints on my purchase -- it served just the purpose I needed it for. I may shortly duplcate it. The price sold me on it. Also I do use it over thick carpeting (no padding)--and all seems fine.
I don't know if any other mat would be better--I just noticed this mat's info says to use with short commercial type carpet and I have thick pad/carpet. My chair does not roll easily. Probably my own fault for not checking the details before I purchased.