I have used all three sizes. I find the 28mm one perfect for cutting curves. I felt the 60 mm blades wore out faster, especially if I was cutting multiple layers I usually use my Olfa 45 mm--the yellow one that you have to compress the handle for the blade to come down. It is the safest I have ever used. I have also tried the Martelli and, while I liked the comfort, changing the blade was a total pain in the you-know-where.