I use Aurifil 50 weight because I love sewing with it. When I bought my Bernina 14 years ago, the dealer said to use either Gutterman or Mettler, I have forgotten which. I use both for garment sewing; but only Aurifil for piecing and quilting. I buy Aurifil on sale so I don't complain about the cost; but I sure do use lots of it.