I have the Simplicity Bias Maker and really like it, but I have been waiting for a long time for the company to produce the narrow 1/4" tip - some kind of manufacturing problem apparently. Several other sizes of tips are available. This method folds both sides of the fabric strip in towards the center of the strip so the resulting bias is actually single thickness except along the edges. The technique which uses bias bars gives a different look as the bias strip becomes 3 or 4 thicknesses of fabric after folding, stitching, re-pressing, etc. I actually like the look of the thicker bias but it really depends on how it's going to be used and your personal preference as to the finished look. I make lots of bias because I love to make Celtic designs (and teach it!) and Stained Glass type of designs.