First I have to say that the 48" dimension included the lip which is not what I expected. Next the mat does dimple with my 185 pound weight. If this matters to you then don't buy this mat. Spend the extra money and get a better one.
Good size but When put on carpet even a somewhat firm carpet the plastic dents and doesn't let my chair move well. The wheels get a bit stuck in the plastic which becomes dented.
This delivery was delayed a few times but when it arrived I was very satisfied. Compared with my previous mat this one lays flat and my office chair rolls easily over it without too much shifting. However I find it dents easily despite my less than considerable weight (<130lbs). This is probably in part because I have rollerblade wheels on my chair so the weight is concentrated on a smaller surface. For the price well worth it. Was delivered flat so no need to worry about uncurling.