I use Coats & Clark Dual Duty Plus on top and bottom (for pieicing) because it's readily available and I can run to Joann's if I run out and I'm cheap so I try to use a coupon if it's not on sale for 50% off and I still consider myself a beginning quilter and don't know better yet and I have two boys who will inherit a lot of UFO's which will end up in the trash if I don't get busy soon. I do clean my machine often to dig out all the lint but I don't mind.