At a quilting sit and sew meeting once, an experienced quilter told the group polyester thread, over time, was more likely to cut your cotton fabric. I was a new quilter, but the others also agreed. Soooo....Since then, I only use cotton thread. But, from reading this board, it seems it's totally personal preference and what works best in your machine.
This really is a quilting myth these days. Poly thread is so much different than it used to be. Google superior threads and
watch all the videos about thread. Some very good information on many subject we talk about.
http://www.quiltingboard.com/links-r...d-t215131.html