I think that KnitPicks yarns are priced the way they are because they aren't of the same quality as other yarns. They're not bad, but you do get what you pay for.
Debbie Bliss Merino is heavenly to knit with. I just started with Morehouse Merino that didn't feel as soft to me as the Bliss (which is superwash) on the skein, but now that it's on the needles, it feels soft and springy and lovely.