Pros : I love my mat. It makes cutting much easier and more efficient for me, especially with small pieces for jewelry. It holds the glass securely, a real plus when designing a cabochon.
Cons : They smell a little at first, and it takes awhile for the odor to go away.
Other Thoughts : You won't totally replace your grid cutting system (especially for large pieces), but once you start using this, you will can't imagine how you cut before.