Canoe camping and kayaking, I always take a synthetic bag because dew is heavy and it is damp when camping on a lake shore. Backpacking I always use down due to weight. Winter camping, I have used down because that is what I had but a lot of moisture accumulated in the down when I did not use a VBL.

Bike touring, I have used both synthetic bags and down bags but I am more careful with the down than the synthetic.

I camped in the rockys for 6 straight weeks with a down bag quite a few years ago, had a brief rain virtually every day but otherwise the air was usually dry and I got by with occasionally putting my bag on top of the tent in the sun for a half hour to air it out.

I think it varies a lot on how humid it will be where you are camping.