I bought a Crystal Caste combat mat at Origins this year to replace the mouse-eaten one I had gamed with in my childhood (too long in storage).
My original mat had been a Chessex mat, and I selected a Crystal Caste one this time because they provide double-sided mats, useful for running GURPS on one side, and D&D on the other.
I was impressed with the design, and it is very pretty.
Unfortunately, I've had less success with this mat than with the old Chessex mat I had. Several of my maps are still visible on the Crystal Caste mat after having been left on the mat for six hours during games. Suspecting that perhaps my markers were at fault, I tested them on both my Crystal Caste mat and my Chessex mat, and after six hours, they removed completely from my (mouse eaten) Chessex mat, but left behind a visible line in the Crystal Caste mat.
So, while the design is both prettier and more functional, I do not recommend these mats for people who draw out their maps on the mat before a game session (which is what I do), but as long as you wipe them down within 2 or 3 hours of marking them, they are quite good.
But if I had the choice, I would go back to my Chessex mat now.