I make a lot of quilts donated to Project Linus, and have now switched to using fleece as my batting/backing. It was taking me so long to get the tension on my Longarm adjusted and slowing me down. I lay out my fleece and quilt top on my large cutting table and use a spray quilt basting to spray approximately a 12" row of the fleece and then smooth out the quilt top on it. Fold back and spray another section. It really holds both layers together much better than I ever expected. Most of my quilts now are just SITD with my favorite block size being 6-8".
If you can buy fleece on sale, it's usually cheaper than batting and you don't need to use a backing fabric. It has saved me a lot of money so that I can donate more quilts. Apparently the kids really like the soft feel of the fleece, so everyone wins!