Apparently many of the super down coatings offered have just a marginal improvement. The Patagonia version may be better. Just rumors until there is a lot of field testing.
With down, it's mostly about the shell. I've been out all day in a snow storm with a down vest on that was fine and it was my outer layer because it had orange on it. Higher quality down is more susceptible to clumping and loosing a lot of loft than lower quality. Synthetics loose as well, just not as much and dry faster.
