I have used it in machine quilted quilts and one hand quilted piece. I like it. It does come through if you use thinner fabrics. My hand piecing was with a linen fabric, and it was fine.
I wash my quilts in the machine - I make for them to be used, not for posterity. I find bamboo to be warm in winter and cool in summer.
Yes, I am a fan. I have made a quilt with wool batting for a friend, machine wash, and it is holding up well.
I think it is softer than cottons.
I think all battings have an environmental impact.