The advice about going to a shop and trying out several is a good one and then stick with that brand. I have used Omnigrid since I bought the first one many years ago and recently got two of the ones with 1/8 marks in black. I only buy other rulers if they apply to special techniques. I know my Omnigrid would probably work but it is easier to get the ruler that matches the technique. Whatever you do..don't mix brands for your general use. They are not all equal even tho they may look the same (measurements that is).