Has anyone ever purchased ever purchased a Martelli Heavy Duty Cutting Mat? I was at a Quilt Show today and saw them. It has a great layout on the mat and there are several different sizes, but they are not cheap. Someone did say that a large Omnigrid was close to the same price. Would love to have a mat that is made as well as this one, but really want to know if someone else has used it and how did you like it????