Saw this product in one of my Craftsy quilting classes. Having been a paper piecer for 25+ years, I was interested.  How wonderful to be able to draw/print foundations and be able to see sewing lines through the vellum for easier placement and more precise pre-cutting of patches. I think that this product  may be too expensive for a large project - newsprint or very thin copy paper is almost as good - but if money were no object, I would use it exclusively. If money IS an object, buy one pack for use on really small or otherwise challenging pieces. You may get hooked!