The Nano Puff is probably a little heavier insulation than I would wear hiking. If it were that cold, I'd probably wear an full synthetic insulation jacket. But, having said that, I have become a huge fan of hybrid jackets that combine more warmth and wind protection in the torso with breathable fabrics to vent a little better.
I wear a Marmot Variant Hoody more often than not as my top layer for winter hiking and snow shoeing. It's a Power Stretch hoody with a Pertex like fabric and synthetic puffy front. The arms, sides, and back breath, but the front give a sense of just a little more warmth.
http://tinyurl.com/lqd2er5
The PowerStretch fleece is more like the stretchy version of 100-wt fleece. The whole thing fits trim enough to work as a mid-layer and throw a down puffy or wind hoody or soft shell over it if it gets cold.
So, the concept is good. Hybrids work to provide some weather protection (mostly wind) and still breath. The placement of the protection on the Nano Puff looks like it might be more of a fleece that sheds light snow than a fleece that offers a little wind protection while still breathing really well.
