I've had this for just over a week now and I noticed that the mat shifts from normal use. Just this morning I measured that the mat had moved 6 inches forward under the desk. It only stopped because it hit one of the legs on the desk. I'm using this on a LOW pile carpet with a 5 caster rolling chair and I only weight about 180lbs. As others have reported the 'nubs' on the bottom of this mat are worthless. Furthermore the thickness of the mat is not substantial enough to warrant being called a 'medium pile' mat. As I said I'm using this on a low pile carpet and the chair makes a noticeable indentation within just a minute a sitting down. I fully expect this thing to crack within a year. Just poor quality in every regard.
Just had 2 of these matts delivered to my house rolled up and stuffed into a a giant box loaded with Stapes There has to be a better way of shipping these things. I've beought this brand and model before and they seem to last 3-4 years which isnt a long time but better than the cheaper models. The one thing I did notice is they are about 2 inches smaller than they were the last time I bought them; I guess any way that a company can save a few pennies helps keep the cost down. Hopefully I will get the same life out of these as their predecessors!
I've ordered this item in the past. As with most plastic mats they do deteriorate over time so they do have to be replaced. The only complaint is the mats were very dirty upon delivery. Not sure if the delivery person is to blame or what but I had to scrub them before I could use the mat. Otherwise no other issues.
This floor mat is exactly as described and works well. It stays securely in place. I was especially happy with the next day delivery of it right to my door.