Overall I am pleased with my purchase ... it is the size I needed and while it came rolled, I placed some weights on it and within a few hours, the mat was lying mostly flat; however, the long side edges do still curl up just a bit. I like the grid underlay as far as layout, measurement marks, etc. My only problem with the whole mat/grid combo is that the mat is so thick that you cannot clearly read the numbers on the underlay; the long side curling on the mat (mentioned above) also contributes to this since the numbers are printed on those same long edges. As stated in the product description, the mat is "semi"-translucent ... so the thicker the mat, the more opaque it becomes; hence, the underlay doesn't really help me a lot since I cannot easily read the numbers. I can see the lines, but even those are not completely visible. Therefore, I will not be comfortable following the lines to cut when I need a precise inch-by-inch measurement. The lines may help to provide a straight edge though. I am a sewist and was trying to avoid the need to put down one of my silicone cutting mats when cutting fabrics. The underlay is a good idea, but the mat itself is just too thick for the underlay to be 100% useful.