I have several spools of Treasure, but thus far, I have only used it for binding (it was closest to the color I needed). I would say it is very similar to Gutermann (which is the thread I have used for hand quilting), and would describe both of them as wiry. I've never tried Coats and Clark, so can't compare. I like the Gutermann for hand quilting, and assume I will like the Treasure as they are so similar in feel.
NJ Quilter, I would say do not take out your silk thread work! They say that silk thread is very strong, and on the Superior Threads site, it is considered suitable for quilting.