There are a lot of good brand suggestions here. My suggestion is find a used one. Lots of folks buy a parka for Denali and turn around and sell it knowing they will likely never need anything that warm again.
Having been on denali this past year I wore my down parka exactly 20 minutes! In the morning of summit day at 17. I would get a used sub-zero on ebay and spend money on a down sweater with a hood. I wore that almost 24/7. Just my .02
I bought a new TNF Himalayan Parka for a good price, used it for an hour on Elbrus on a stormy summit day, but it was too warm. Love the jacket though. Would recommend it and take it to Denali without doubts.