Fins_N_Tines
WKR
Pretty much got the same answer form Western Mountaineering that Matt G at FF when I asked them a few years ago:
Thanks for your email. This might be a lot more info than you bargained for when you asked the question about treated down.
Currently we do not offer any bags with hydrophobic treated down because as of today we still have no compelling evidence that it provides better overall performance throughout the life of our product. We have been testing treated hydrophobic down from three of the major industry suppliers (i.e. DriDown, DownTek, and ResistDown) since December 2013 but nothing has prompted us to strongly consider using it in our products based on the collective feedback from the tests thus far. Our plan it to continue testing for long term performance comparisons but up to this point we have been underwhelmed. Comparing any of the treated down with our goose down is like comparing at the fresh powder snow in the backcountry to the slush in the parking lot of a ski resort. We currently don't have plans to use hydrophobic down in the near future.
We have done quite a bit of testing and due to multiple factors we have seen little performance difference between our down and hydrophobic down. A few of our tests have involved sending out sleeping bags and jackets that were cut in half and have one half hydrophobic one half normal down. In every case users where unsure which was which or if there was a difference at all. These samples were used for months at a time, some of them for nearly a year straight. We believe this is because of the water resistance and breathability in our shell technology.
DriDown, DownTek, and ResistDown)
Although I have not seen a real-world difference between treated and non-treated down, the 3 treated downs referenced above and by WM are in my opinion the standard in REI type box stores, but not as good as Hyperdry and Quixdown. I would much more rather see testing with these two as they are used more in hunting companies.