I love my Stripology ruler. I have been piecing quilts for a couple of years. Too often the ruler moves while I am cutting When I use the stripology ruler I am much more accurate. There is a definite learning curve. You have to remember to set the end of your fabric on 0. There is a nice white line helping you, but there is a black line that at the beginning I made cutting errors. My ruler has stars for every 2 1/2 so you don't have to do the math, It has squares, filled in circles. I really do like it.