For me it depends on the time of year and the weather Im expecting. I tend to think of it as 3 big seasons. Summer, Shoulders and Winter.
Full summer and I know that I will just be wanting a something light to keep the chill at bay during the night then Ill bring down if the weather forcast is somewhat decent. Most of our summer squals hit in the afternoon and are only on you for a few hours. That I can deal with while wearing down and a rain coat. However If I am expecting rain/clouds over the entire trip than I might grab my Shoulder season favorite, my synthetic Patagonia Nano puff.
For me again this garment ends up being a real shoulder season mainstay. If Im expecting to be in wet spring snow where the temps arent low enough to keep everything frozen, or if its rain in the forecast for every day then Im not going to even try to worry about keeping down dry/figuring out how to dry it out once it is wet. I will just take sythetic.
But then once full winter comes around again and the temps drop down to where all forms of moisture are freezing, then down becomes the go to garmet again. When all the condensation and or snow is freezing, then its simply a matter of brushing it off to stay dry.
Of course I have a variety of layers to fill the rolls in these three main seasons, depending on the temps and my forecasted level of activity. A few of my absolute favorites which fill probally 98% or my insulation needs are the Montbell UL down vest, Feathered friends hooded helios down jacket, Patagonia R1 fleece and Patagonia Nanopuff.