I used to review tools for Threads magazine. I purchased a FabriCalc and do not use it. My feeling is that if a product is so difficult to understand and you have to use it repeatedly to remember--well, the darned thing is useless. Figuring fabric? I use the old method even after 30 years of quilting: gridded paper and draw it out. That way I know exactly what I have designed and how much fabric to buy. And I don't have to relearn the process each time I do it.
Sandy