I prefer the Hobbs 80/20, Quilters Dream Request, Legacy 80/20 or 100% cotton or Tuscany 100% cotton. Washable wool (Hobbs, Tuscany) also needles very easy and it is a pleasure to quilt it. Of course you can also use a low loft poly batting!
I don't like battings with a scrim for hand quilting, it is not so easy to quilt them and I can't reach the result I would like to have.