I generally piece with gray Aurofil 50wt. that I buy in cones, check out the prices at Bear Creek online, I have found them to be the most reasonable. But I have also pieced a quilt using Wonderfil's Decobob on top and bottom and really liked the results of using such a thin 80 wt. thread. I went to an "infommercial" thread class at a local quilt shop that has begun carrying the line and saw examples of using both Decobob and Invisifil which is 100 wt. for piecing and quilting. The difference in the feel and weight of the pieces was amazing! When I run out of my cones, I will probably switch to the Wonderfil. The Decobob is a cotton wrapped polyester. So far, I have just sent my quilts out to be quilted so I can't speak to what I might like to use to quilt, but again, I was impressed with the drape of heavily quilted pieces using the Invisifil.