First off, I love, LOVE, LOVE aurifil thread. It's wonderful. But, if you're machine will ONLY take Aufil I think something's wrong with it. I do try to use high quality thread, but I can switch brands with no problems. Yes, good thread makes a difference, but if your machine (especially if it's a new one) will only use one type of thread, I'd say it needs servicing of some kind.