R2 vs Nanopuff

My vote is for some form of fleece + a windshell.

I couldn't walk in any form of nylon coated insulating jacket, I'd just cook.

How cold a temps are you talking, It's gotta be pretty cool for me to want more than a base + windshell when mobile. ie: below freezing by a few degrees.

Fleece excel's in this aspect as you know because it'll breath, it's heavier and a syn/down insulating piece is warmer for weight but get's sticky inside if active.

The Nanopuff (and similar garments) are great: they're light, compressible, warm, and windproof. All these things are great, unless you want to exercise with it on.

For warmth while moving, fleece is king. It's a bit heavier, not quite as warm, durable, and super breathable. Of course, this means it isn't as good if you aren't wearing it (i.e. it's in your pack) or aren't generating much body heat (i.e. sedentary activity).

Tradeoffs. Pros and cons.

As folk say already fleece and primaloft are two completley differing fabrics.

Fleece excels for its breathability and quick drying and primaloft for its warmth ( not as good as goose down though)

Primaloft can be worn while active but it would have to be fairly cold.

I have a down sweater so I have the colder end of the spectrum covered. I got the Nano Puff to cover the 45-60 degree evenings/mornings. Plus I liked the smooth fabric that allowed easier layering. However, I think breathability and thus being dry (not sweaty) is hugely important to maintaining core warmth. For that reason my sense is the R2 is better in that temp range than the Nano Puff.

R2 is generally to warm for on the move … especially in poor weather where youll need to put it under a wind/rain jacket

the R1 is much preferable, or a cheap 100 wt fleece … perhaps even a vest version

the REAL use of a nanopoofay is as a layer where you put it over a windshell for stops/belays … and perhaps for slow descents or when slowly active … it offeres some weather resistance without having to put it under yr shell … ie not having the faff of taking off yr shell layer constantly

"I got the Nano Puff to cover the 45-60 degree evenings/mornings. Plus I liked the smooth fabric that allowed easier layering. However, I think breathability and thus being dry (not sweaty) is hugely important to maintaining core warmth. For that reason my sense is the R2 is better in that temp range than the Nano Puff."

For that I'd be taking either the nanopuff or your down, after all your type of usage is just camp use, not active by the sound of things. If your not on the move in cold temps the insulated jacket IMO is the better choice. The breathability of the fleece will be redundant as it's for camp use only. At those temps even starting off on a cool 45°F morning the fleece will be too warm anyway (you might get away with the first 5-10minutes but after that you would probably cook).
A nylon shelled insulating jacket should breath sufficently around camp, it's just when active (walking fast) the issues can start.

My thoughts for fleece/active are sub 25°F weather while actually walking. Warmer than that and it's just base + windshell.

I agree w/ Eric that for on the move, R1 is probably a better bet than R2

as pointed out, fleece isn't going to offer you much for warmth at camp or on breaks- primaloft will, it can also help w/ bumping up your sleeping system, much better than fleece

I have several R1 pieces, but they only see use during winter or cold/wet shoulder season- in those situations I always have an insulating layer in addition to the R1

for three season use an insulated garment (syn or down) is going to trump fleece in almost all situations, outside of three season use the fleece is great for on the move, but is going to be in addition to an insulating garment

I have the R1 hoody, it is strictly a winter base layer for me because it has such a trim fit. It sounds the general consensus is the Nano puff is a better all around piece than the R2. Though I still think the Nano puff is a little warm for the summer alpine conditions I am talking about.

I have a Nanopuff and love it.

However, the most I exercise in it is walking around town. In the backcountry, it is for camp and rest stops only.

My newest acquisition is the Smartwool Midweight Hoody, and I love it:
“Consider this top a zip-neck with a balaclava attached; its clean-fitting, three-piece hood stays put when you pull it on and layers easily under a helmet so you get all the warmth you need with out any distractions. Midweight merino wool offers excellent warmth, breathability, and natural odor-fighting capabilities. Engineered thumbholes offer extra warmth and a no-gap fit under gloves. Shoulder panels eliminate top seams for comfort wearing a pack.”

I will just add my voice to others. Unless you are talking sub-freezing conditions, both the R2 and the Nanopuff will be too much insulation while hiking. In fact, I think anything more a mid-weight base + wind shirt would be too much above freezing. As was suggested by others, as you get near freezing, something like the R1 or 100wt fleece start to be useful while moving. Puffy (down or synthetic) are useful if you are moving slowly in cold weather, or as a warm up (when stopped) in warmer conditions. Richard posted the classic best clothing combo here several years ago which I would recommend you taking a look at. I tend to run a bit hotter than Richard so I use a bit less insulation, but the general description is very good.

–Mark

I've done 6-8 hour hikes in the snow in 10 degrees F or so, and I find that I can't wear much on top without sweating. Sometimes the wind resistance is key though. I find myself typically wearing a long sleeve smart wool mid-weight and a zipped open wind shell.

I love my nanopuff pullover, but for me, it's only good for stopping or around camp. Still, it works great for that! I find that it is good for breathe-ability in terms of me not getting hot or sweaty when my activity level is low.