I like cotton for piecing, but for quilting, I am starting to find that the polyester has a nicer look to it and also doesn't shred like the cottons do. Even with a large needle I was still getting a lot of breakage on sulky and aurifil cotton thread, YLI ha less breakage but was super linty like crazy, polyester is less linty, had no breakage while quilting. I do find for piecing though, I really like how cotton thread lays, but thats just me. I say use whatever one likes