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I haven't used the Fairfield 80/20, but have used Hobbs 80/20 and liked it. I doubt that the 80/20 would be needlepunched through scrim. Warm n Natural is needle-punched through scrim which makes it extremely stable, but also gives it a slightly stiffer drape. Hobbs 80/20 has a very soft drape. Its biggest difference from non-needlepunched 100% cotton batting is that it has more puffiness and is much easier to hand needle. (Both work great for machine quilting.)
Quilter's Dream is needlepunched, but not through a scrim. The needlepunching gives it a lot of stability but does not stiffen the drape. Quilter's Dream will work up thinner than Hobbs 80/20. A lot of hand quilters like Quilter's Dream. Machine quilters may find it on the flat side and want more "puff".
The Hobbs 80/20 is not needlepunched, which means you need to handle it a little more carefully when layering. Quilter's Dream will result in a flatter effect than 80/20 because of the needlepunching. Warm n Natural will be the heaviest and stiffest because of the needlepunching through scrim, but its stability will mean that quilting lines can be much farther apart than 80/20. The scrim also makes hand needling a little more difficult. As someone else mentioned, the scrim also makes WnN heavier in weight than 80/20 batting.