Another thing I question for backpacking and being mainly a hiker that camps than a camper that does some hiking is having a puffy in the first place given it's raining. That means it's not that cold. For me more often than not it has to be colder than 32* to warrant a puffy being carried unless its very light wt and as others said it would probably be a synthetic. Of course conditions change. I'd much rather have a greater number of thinner layers in my apparel system - up to about 4 layers- than 2 or 3 where one of the pieces is a major(main) heavy insulation piece as in a puffy potentially made even less versatile possibly even more redundant if its hooded. Again its raining. I'd find very good versatility in something like a med 150 wt merino or lite silk base layer V neck tee, 1/2 zip med to med heavy wt merino or one of the new Capilene mixed materials LS 1/2 zip shirts that mix merino and synthetic, lite synthetic VEST like a Nano PuFF with my rain shell over the top. That's 4 layers. But accessories like beanie and UL to med wt gloves round out many versatile combinations addressing wet conditions from 25* to 70*. Again depends on your approach to hiking, what else is in your kit, how significan't the conditions can or are expected to change(like if you're near treeline and possiy will ascend above, exposed on the open plaines where quick moving heavy rain fronts accompaned by high winds sweep through dropping temps and chill factors significantly as can happen in windy strewn open deserts, climbing, mountaineering, or having mixed trips), and how well you know how to bring all your gear and skills to bear on the current conditions.