I've been getting the best results since I switched to Aurifil 50 wt for piecing. Got it on clearance from www.tristan.bc.ca I got the tip from Candace of elkgroveorchids.net. She's on this board. I put her name and email in the comments for referring me. I never would have tried it if not for the sale. Now I'm set for life (almost)! No tangles, fraying, breaking, and markedly less lint. Helps get that perfect 1/4" seam. I also like Masterpiece, which is 50 wt, by Superior Threads. They make a 60 wt poly, but they recommend cotton for piecing since it will be pressed with a hot iron. Just passing along what I've been fortunate to learn.