I was at a retreat this last weekend and a Bernina dealer was there. She was sewing next to me. She had the top of the line 830 Bernina. Her thread kept breaking. She said I can't use Aurifil on my Bernina, it doesn't like it and that is the thread I packed not thinking about the machine I was bringing. I said I thought Aurifil was one of the best threads. She said it is but the new high end Bernina's sew at their best with poly thread.