I like Omnigrids mostly. I don't like the ones that have more lines on them than I can keep track of and some of the ones with color other than the yellow of Omnigrids makes it hard for me to see where the edge of fabrics are. I've also noticed recently (last couple of years) in the beginner quilt class I teach that there are so many rulers out there that are confusing on their markings. The beginners really have to get to know their ruler so they are accurate in their cuts.