They come in such a variety of fabrics and colors and they are pre-cut for you. When I was at Eleanor Burns California store, I mentioned to a clerk that she had not come out with a book for jelly rolls, they were a couple of years old by then. The clerk said generally you can use them in most patterns. I found one of El's books and sure enough made a beautiful quilt. I think the best thing about them other than being pre-cut for you is that you get such a good variety of fabric. I generally ask if there are 40 different fabrics as some local quilt stores will put in duplicates of an ugly fabric (sorry, all you owners out there, but it has happened 3x now to me). I really like all the precuts out there.