I absolutely LOVE wool bat and have had not issues with it. It's a dream to quilt through, is light and drapes well and it breathes so don't get overly hot yet is plenty warm too. I've used it for baby quilts and ones that go to the g-boys--so since they are very young, that often means a washing the next day!
I like to use a wool bat on top of a cotton bat (Hobbs 80/20) if it's for show or when I have a quilt that has embroidery or applique that I want to quilt tightly around so that it pops like trapunto--but the lazy girl way!