The Brothers Rep at classes I've taken says that polyester thread is his favorite for embroidery - not rayon. It's shiny like rayon, has virtually no lint (the big problem with cotton) and comes in a wonderful variety of colors. For that reason, I've become a BIG fan of Superior's Rainbow variegated thread. I LOVE Superior's Bottom Line bobbins, too. I stock up on both Rainbow and bobbins at quilt shows where Superior usually has great prices! Otherwise, I order from their web site.