Totally agree with everything stated above. Had the original super down ultra and sold it. it was marketed like it was some magic potion for warmth, but the fact is the amount of down fill is more important than even the rating of the down fill. Lots of 650 is still warmer than a medium amount of 850.
I thought my Patagonia Nano Puff was warmer than the kuiu down jacket.
A warm down jacket starts at 5 oz. of high quality down and goes up from there.
If one of the hunting companies could make a 20 oz or lighter jacket with 7-8 ounces of 800 or better down for under $400, I think they'd struggle to keep them in stock. Ultralight down jackets that are no warmer than your $30 fleece hoodie don't make much sense to me.