I understand from the woman at the LQS that Coats and Clark has changed the way they are making their thread---I agree because I bought a spool recently and it's AWFUL! It's wiry, stiff, and linty. LQS refused to carry any more.
My stepmother (a professional quilter and instructor) told me the worst thing I could do for my Pfaff was using Coats and Clark in it. So now I piece and sew with either Gutermann's or Metrosene.