Interesting coincidence. I teach free motion quilting (on domestic sewing machines) and have a running conversation about batting with my students. I have been making samples with the same stitching designs on quilt sandwiches where I am using cotton batting, wool batting and polyester batting. I did not have the polyester so I bought some of the low-loft from JoAnne's. Won't buy it again.
Love the puff of the wool will use it for wall quilts due to its recovery and memory (less creases when folded), use cotton 99% of the time because I like the crinkly look. The polyester was uneven, lumpy and very slippery.
I understand why some use the poly due to its cost or availability, but if I am putting the hours in on a quilt, I am going to buy the best materials possible, and IMHO, polyester batting is not it!