Until last year, I'd always used Olfa's. In the span of under 3 months, I broke not one, but two. Well, DH broke one of them and I the other - both the same way. Taking them to a class when it was cold - they became brittle and cracked when moved.
At about the same time, I'd started getting notices for Martelli's red line promotions. I now have 2 of their mats as well as their revolving one. LOVE, LOVE, LOVE them. I can feel the difference when cutting, it's more cushioned and much smoother. They can be ROLLED for storage. They won't warp in the heat or crack in the cold. And - get this - you can IRON on it! I've done it. The first time was scary, for sure, and not sure I'd recommend it as a constant thing to do. In this case, I was at a class where we used fusible interfacing, placed small pieces of fabric on it, and when satisfied with the layout, fused it down. everyone else had to transfer their fusible web, very carefully so as not to disturb their planned design. Meanwhile, I took the iron and pressed the fabric to the fusible right where it was laying on my mat!
If you sign up for their redline promo's, which is not the same as signing up for their newsletter, you'll get e-mails of upcoming sales. Each time they feature a different one of their products. Sometimes it's their blades and cutter, sometimes mats, sometimes templates or rulers. Once or twice a year, it's for all of their products. Fifty percent off is still expensive, but honestly, I can't imagine ever having to replace this.