This is a beautiful coat. Extremely thin and lightweight. I have a pair of Columbia pants that uses the Omni-heat reflective technology so I know it can add significant warmth, but it's not miraculous. If you need a coat for sub-freezing temperatures, I don't think this will be sufficient as your only winter coat.This morning the temp was 31 degrees and according to weather channel it "feels like 26". There was a slight wind and sky was totally clear. I stepped outside w/ my normal under layers - a North Face mid-weight base layer plus a Columbia fleece pull over - these are what I usually wear in my house (set at 68 degrees F), then this coat, plus gloves. I also have my Columbia omni heat lined pants on, because the coat is not long enough to keep my legs warm. It reaches my mid-thigh, and only mid-calf length can keep my legs warm. I also have the hood up. coat zipped all the way up. I stood outside for only a few minutes - less than 5 minutes I think, while my breakfast was cooking on the stove. It was Ok. I wasn't "toasty", but wasn't really cold either. Just a hint of chill. If I were walking or doing moderate activities it may be warm enough. I do have a heavier down coat that goes below the knee and that definitely feels warmer, but also make me feel like a mama bear. The Mighty Lite is perfect when you need to be more nimble and active, or when you need to sit in a car, or shop in mall so you don't over heat or having to carry a big heavy coat. It's not warm enough for 20 and below. 30s is ok if you are at least doing some moderate activities and layered well. That said, everyone's tolerance for cold is different. Yesterday I saw someone walking in short sleeve and shorts without a shiver, while I was bundled up in 3 layers. That sight alone sent chills down my spine, literally. If you are like that lady who can stroll around in 40s weather w/ merely a T shirt and shorts, the Mighty Lite may be all you need in a winter blizzard, but for me, this is a nice fall coat, or a supplemental winter coat for certain situations.I have also tested the coat in light drizzle. Water resistance seems good, but don't count on it as a real waterproof rain coat in torrential rain. It's not made for that.This coat is true to size. I have many Columbia clothing sized between Small and Medium, and for this coat I purchased a Small. It fits well, with room for middle layers. However, the cut is generous for underarm/bust area and very slim in the hips. My hip measurement is larger than my bust line so the hip fits snug while the top is very roomy. If you are top-heavy you will likely fit better in this coat.This coat is so sleek and simple you can slide it on and off easily and quickly. No buttons, snaps, draw strings or velcro. Hood will stay on (at least on me) if I zip it all the way up. Once the zip is all the way up I can't even take the hood off! Thus the lack of hood draw string is not a minus for me. Because it's so thin and a bit fitted, I can even wear it under my long down coat in case I need to go to an extremely cold place, like Alaska or something.The "nocturnal" color is a dark grayish navy-blue in case you wonder. In daylight it's navy blue. In tungsten light it's dark gray. There's a slight sheen as represented by the photos. It's a pretty color and goes with just about everything.The bottom line: omni-heat lining is awesome but not magical. There's no replacement for super long, thickly padded high fill powered down coat that resemble a rolled comforter with arms. That said, this coat packs well, looks cool, keeps you warm (to a certain degree) and is very practical.Note: the omni-heat works by reflecting your own body heat, so if you rush outdoors as soon as you put the coat on, you won't feel much warmth. It's best to wear it for at least several minutes indoors to build up the "heat". I noticed this w/ my omni-heat lined pants too, so I usually wear them indoors too as they don't overheat as long as my room temp is set at less than 70F.Update: not a fan of the main zipper. I like that it's a 2-way zipper so you can open from the bottom to allow more room when you sit in a car, etc., but the zipper is hard to start. The tip won't go all the way in more than half the time. Once it moves it glides fine on the teeth, It's very frustrating when you are in a hurry.