Does this new-fangled "Hydrophobic Down" stuff actually work? Does one still restrict a down duvet to cold/dry days, using a synthetic one otherwise, or can a hydrophobic-down duvet cope with more than that?
In reply to Coel Hellier: My hydrophobic down jacket has been drizzled on in weather which would have felt like it was making the down in my none hydrophobic jacket loose it's warmth, and didn't affect it to the same degree, in letting 're volume' faster. It would still lose it's warmth like normal down would *I would guess* if it was caught out in heavy rain and you couldn't get anywhere dry.
One good side of hydrophobic down might be that one's pong doesn't stick to the down in quite the same way, but I dunno about that.