I have used both.
Hobbs 80/20 is softer and lighter in weight, and its loft is soft. That is, if you push on it it compresses but springs back when you let up. It is easy to hand quilt. It is not needlepunched and has no scrim, but is a stable batt. It needs to be quilted more closely than W&N because it is not needlepunched through scrim. After being made into a quilt, the quilt is a little more like the more modern comforters in that it has some loft.
W&N is heavier in weight and flatter. It is considerably harder to hand quilt because of the scrim. The needlepunching through scrim makes it very stable, which is why quilting lines can be so far apart. The end result is a heavier quilt than Hobbs 80/20, a stiffer quilt with less drape (although it does soften up some with each washing), and a flatter quilt quite unlike modern comforters with their lightness and loft.
My personal preference is for Hobbs 80/20.