It stands to reason that exceptional quality sheep produce exceptional wool. Fleece quality is one of four standards of excellence we breed for, and it shows.
Genetics impact wool characteristics, as do nutrition, health, age, and gender. Generally speaking, virgin lambswool is the softest, and has the finest micron count, so it usually goes for a premium price. Lambswool, not first clip, is also premium, although not always as downy fine as virgin. There are exceptions to this, some is good fortune, some bloodlines, and some have a higher degree of New Zealand genetics which tend to produce loftier fleeces.