I have her log cabin rulers, and I also took her Craftsy and for myself I love her method, I made a king size log cabin quilt in less than a week,my blocks were square and I had nothing to trim down and my quilt ended up perfectly square thus making my very first king size quilt a painless and fun process. Chain piecing was quick and easy and because everything is cut exactly to size it creates less headaches.
Specialty rulers are a personal choice, I have no issues buying something that help she me achieve better results and some rulers are better than others, but IMHO her log cabin rulers are worth the cost and her methods are by far superior to other methods I have seen and tried.