The funny thing is, you will find totally contradictory reviews because we all work differently.
For instance, I can't stand rulers with a lip or rulers that have ridges on the back that prevent it from sliding smoothly across the fabric when I want it to! I don't like rulers with the extra 1/2" added to them (except for the 12 1/2" square). But some people love all those things!
I love my big white cutting mat because it is 30" x 36" instead of 29" x 35" like the green ones.