If you need to protect a large work surface, this is your mat.
I just bought my second Martha Stewart portable folding cutting mat. I also have the 18x24 mat which is definitely more portable. I work on a pretty expensive desk and I have to cover it completely for fear of damaging the wood. I swear by this cutting mat. The larger 24x36 inch size perfectly covers my desk, takes a lot of punishment from all kinds of crafts, and is easy to clean. It's also thin enough that you don't have that "spongy" feel you get when working on other protective surfaces (e.g., WeR's ubiquitous pink mat that comes with many of their products--notably the Sew Easy series).
The smaller Martha Stewart mat (18x24), which I also have for smaller surfaces, is more portable if you need to take a mat with you, although I'd probably use the Basic Gray magnetic cutting mat for its greater portability (although BG has apparently stopped making them--get one while you can!). All 3 mats "regenerate" which I guess means if you cut them, the ding closes back up. I do know the MS mats are not heat/sun tolerant--I ruined my first large one by leaving it in the back of my car in the sun for a week. So they can't regenerate from all forms of abuse!
Therefore, if you can keep them out of the sun, you've a cutting mat that will last for many years. I recommend either MS cutting mat, depending on the size of your workspace. You won't be disappointed. It's a great working
surface for all sorts of crafts.