The article mentions the big difference between eiderdown and other downs, but doesn't really stress it. Eiderdown is different than all other commercial downs in that it is harvested from used nests, rather than directly from the bird. The birds pluck their own down, use it to line their nests, raise their chicks, and then the "farmers" collect the down after the ducks have left. All other downs are plucked by humans from a dead (or dying) bird.
I was excited enough about eider down to plan a vacation largely around it. Instead of Iceland, we went to the Vega Islands off the north coast of Norway. It was a beautiful area. The BBC has some nice pictures here: http://www.bbc.com/travel/gallery/20181001-the-worlds-lighte....
That's pretty horrible - but I skimmed through that and I didn't see any eider ducks (could be wrong though) - they are quite distinctive looking birds.
They are hard to compare directly, since the "magic" of down is its compressibility, whereas aerogels are typically rigid. Eiderdown is actually on the lower end of elite downs as far as loft, which is measured as "Fill Power" (FP): https://www.researchgate.net/figure/Fill-power-values-from-e...
That said, there is a new synthetic sleeping bag insulation that is using some amount of added aerogel fragments. Compared to that, high FP goose down of 800 or 900 FP is still much better insulation per ounce: https://backpackinglight.com/forums/topic/new-ul-synthetic-i....
I don't know if it's in any way a useful comparison, but combining the two links, one might conclude that eiderdown at a 500 FP is about as insulating as PrimaLoft Gold with added aerogel.
I was excited enough about eider down to plan a vacation largely around it. Instead of Iceland, we went to the Vega Islands off the north coast of Norway. It was a beautiful area. The BBC has some nice pictures here: http://www.bbc.com/travel/gallery/20181001-the-worlds-lighte....