I prefer using 100% cotton in my quilts. Years ago I made a baby quilt that got used and washed many, many times. Had the opportunity to see it again about 15 years later and I could not believe how *soft* it had become. It was like hugging a cloud! That quilt was made with Mountain Mist Blue Ribbon 100% cotton batting.
Years ago I used Warm n Natural a lot, but I eventually came to dislike the stiffness of the drape.
Just read an article about bamboo that says the fiber has to go through very toxic processes to be made into batting. It is often touted as eco-friendly, but cotton is actually more eco-friendly in terms of processing.