Patagonia nanopuff or down sweater?

Normally I'm a big fan of down but recently I acquired a Nanopuff. I successfully layered it with my Alpine Light Parka for the coldest parts of winter — and I intend to use it as my insulation layer this spring. Wearing it out and about the neighborhood and the trail, I was surprised both by how warm it kept me down to the low 30s and by how well it seemed to breathe. Now, I could take this all back after another couple outings, but so far so good.

i have both and would have to say that it depends on your intended use.
the down sweater is warmer than the nanopuff for sure. I find that if i am going to be even semi-active i go for the nanopuff. it breathes better is less bulky and the down sweater would just be too warm. I have only worn my down sweater once while being active, it is usually way too hot. that said the down sweater is a great piece for nights at camp, extra sleeping insulation etc. I wear both of these jackets in daily life as well, and the down sweater is my winter coat. I've gotten the nano preety wet a few times with no wetting through or noticeable insulation loss. I've used it for some snowplay etc. You say you generate alot of heat when you move, i'd guess the down sweater would be too much while moving.

I'd say if you are looking for pure warmth go with the down sweater, but if you want to use it while active go with the nanopuff.

I too have both, and agree with everything Ben said. These two items are completely different in function, and if I were you, I would keep both. If I were to keep only one, I think you would use the nanopuff more. It is my go-to 3 season insulation (all I need if temps are 30 F or higher), and I use it similar to how most people use fleece. Mostly camp wear, but may be worn when active in very cold weather. I am also less concerned when wearing it in wetter conditions than I would be with down, and it dries quickly.

In the winter I throw a down sweater hoody on top of the nanopuff for in camp use down to -15 F temperatures (with a couple base layers and a windshirt). I also sleep in it. The down sweater is not the lightest down garment out there, but it is well made and the fit is great for me.

if you don't already havy light weight synth and down layers i'd keep them both. If you do, than keep the nano. Its lighter, more compressable and warm enough for 3 season. Also more versatile as others said. Where'd you get the nano for %75 off?

Thanks all, may be I will keep both esp considering the prices I paid :-)
There was a sale in Toronto store – it was posted here.
first 50% off, then a lot of stuff at 75% off.
I spent way too much there… :-) That's why I was thinking of returning some of the
stuff.

if the down sweater fits under the nanopuffy without much compression … keep em both

using both together is a good jacket for milder winter conditions and shoulder seasons

Hey, did the 50% off @patagonia Toronto turn to 75% off for the nanopuff pullover? If so I'm going to go back for a price adjustment!
I think the Nanopuff is like a 200 weight fleece (a little lighter, less durable, a bit less breathable, but windproof). I had a pata down hoody that was maybe like a 300, maybe 400 weight fleece, bought a ED downlight on sale which was warmer – makes a great winter jacket in TO.