With the exception of my sleeping bag I have yet to take any down garment to Alaska. I've done five trips (not counting ice climbing trips in Valdez) to climb in different parts of Alaska since 2009 in either winter, spring, summer and fall.
My choice of kit in Alaska is based on my experiences climbing in the lower 48 (OR, WA, ID, MT, WY, CA, CAN).
Down garments potentially have a place in one's kit but that is for each person to figure out for themself hopefully before they tackle their bigger objective.
What do you bring, John, and for what temps?
I've only got two puffies myself - a ginormous-looking NF Nuptse and a light synthetic compressor. Not sure when I'd be in the market for a new coat, but should I keep getting out in Winter or headed up to Denali, I may.