I use Gutterman, Sulky, Isofil, Mettler, Coates, Dewhurst, (some of it old, inherited stuff), Signature, Superior threads, Wonderfil, etc etc. They all serve a purpose for different jobs. The only ones to avoid are the hand quilting threads which have a coating on them that interferes with tension discs and the el - cheapo threads that break all of the time.