I purchased them at Home Depot on a Friday, and took them back on Monday. They off-gassed and smelled so badly that I could smell them on the 2nd floor, even t hough they were in the basement. Now I've got 2 wool braided rugs down there, and between those and my birkenstock shoes (I live in Oregon, after all), I can quilt for hours. Besides, the rugs are prettier than antifatigue mats.
However, here at the shop we've got them behind the cutting counter, and I don't know how I'd live without them here. Be sure to give them the sniff test before you purchase them, and make sure that you can stand them.