This will keep you plenty warm in the low temperatures all winter long. When I first wore it, I forgot to take it off when I got inside and then realized I wasn't getting to warm even though I was still wearing this really warm fleece. It definitely regulates your body temperature to keep you at the right temp all day long. I bought it as a mid-layer for snowboarding, but works perfectly well in the cold as long as there isn't wind.
It is a tiny bit of a slim/athletic fit, probably more than most, but i wanted something like that so it fits me great (me 6'2", 205lb, 38" chest, 34" waist).
My only gripe is the hood - while I'm glad it comes with one, it's rather large, almost enough for a helmet. I can't really complain since I do like it, but since it doesn't have any way to tighten for a better fit, I'm a little torn on it. It also comes with thumb holes in the sleeves, which are a nice little addition.
This is my first Narrona purchase, and I am definitely impressed. I looked for a long time before purchasing a mid-layer, and I'm so glad I chose this one. I get plenty of compliments wearing this out around town or in the house.