I used to only buy synthetic due to my concern about wet down..... so, I know where you are coming from. Main reason I switched to down is because synthetic UQ and TQ wouldn't fit in my pack.
I like the down a lot better and won't be going back. *for "puffy" jackets, I still prefer synthetics.*

This is what I think:
if a person has a "habit" of soaking their sleep gear, I'd recommend synthetic.
Really, I'd recommend a better method of keeping it dry.
If you can keep synthetics dry, you can keep down dry.
If your down or synthetic is completely soaked thru, your going to be cold either way.

as far as dridown/resist down.... I have a UQ with it. I haven't really been able to test it side by side to verify that it'll dry faster than non-treated down. I don't believe all the numbers(dries %33 faster,etc) , but, am sure it will actually dry faster-which is why I got it.