I use Glide almost exclusively and purchase it from the bobbincentral website above. I tried several brands before settling on Glide. The Connecting Threads poly is 70wt, therefore relatively fine, and it broke frequently when I tried to use it on the frame. Signature and King Tut cottons both worked fine, but created a lot of lint in the bobbin area. Glide is the easiest for me to use because it never seems to shred or break on me. I may experiment some more in the future, but for now I am happy with Glide. (Oh, and I love the Magna-Glide bobbins for Glide; however, I also wind my own bobbins.)