I have had some down bags " wet out" to a degree, but, not my original Marmot Mtn. from the Grand Junction days, just a fabulous bag I used from 1978 to 1999, when it was stolen from my home here by vermin who are most fortunate to be unknown to me...I am not the "liberated" type........

I DO use a VBL in my winter down bags, especially with my wpb-shelled ones and wearing silk weight MEC synthetic longies with it makes it far more comfortable. Mine is also a silnylon one from Integral Designs of Calgary, AB. and FAR nicer than my old coated-nylon Marmot one in respect of comfort. You get used to them and they DO work.

I seldom camp in real cold for longer than 3-4 nights, so, I am good with my Valandre bag to roughly -20F and am too old to go out in colder, although I used to do so often.

I tried the MEC synthetic OB and down inner technique 30 years ago, didn't care for the extra bulk, weight and it did not work any better than what I usually use. I like a highend down bag, eVENT bivy/bag cover and VBL better than anything for sold sleeping and also use an Exped 9DLX with an EVA foam under it...works for me.