I so love my Cr Grids. I have the 2 1/2, 3/12, and 4 1/2 for my mini cuts. The lines are narrow for precise cutting. I liked my omnigrid with yellow outlines until my eyes started to blur on me. I replaced my 6 x 12 and 6 x 24 with frosted Olfa's which I also like.
While on the subject of rulers, it's advisable to replace them when edges become worn. I was wondering why my width of fabric cuts were bowed, and realized the center of the ruler around the 10-14" marks were worn down enough to make a difference when I cut strips 1" or narrower.