I never would have thought I would be particular about cutting mats, but when I went to replace my last one, I found out how particular I can be. I like the lines to go throughout, but I really like the numbers (all of them, even half and quarter) to be on the outside of the edges so that I can see them when I'm lining up the ruler. I also like to have the angle marks included for trimming up HSTs.
This one posted looks like a good one.