I prefer batting to fleece. If you live in a very cold area especially during the winter, you may want to use the fleece. I have used polyester, poly-cotton and 100% cotton batting and like using them all. For children's and charity quilts, poly works best. For special heirloom quilts and special gifts, I use cotton. For table runners and table toppers and wallhangins, I prefer to use the polyester and poly-cotton. Some people will make a flannel top and use fleece to back it. No issues or problems. It is up to you to decide what you want to use for your projects keeping in mind how much use they will receive.