Rating: 4 / 5
(gets a 4.5/5)
Weighing in at 18.4oz/530g the Marmot Atom packs big warmth in a small package.(Did that sound like a Backpacker magazine tagline??) Actually it's true, this bag is warm. It is rated at 40F/5C and I concur. I find it comfortable, with adequate clothing, at 40' and survivable at 30F/0C. By survivable I mean no hypothermia, most bodyparts warm enough, but not always a comfy nights sleep. This is my first bag that has lived up to its temp rating! Sewn through baffles limit the bags warmth, but the lack of side baffles make up for that. I have moved most/all of the down from the bottom to the top essentially creating a nice and puffy top bag.
Positive features: silky-soft interior fabric, water-resistant exterior fabric, 900 fill down(material listing downgraded to 850+ as of this year hmmmm), no side baffles allows down to be shifted for temp regulation, no snag zipper, tapered cut for a close fit, full hood, quality construction, no extraneous features, hot red color makes me feel like I'm going fast while sleeping, turns rocks into marshmallows while conquering mother nature's deadly onslaught(oops, that was Backpacker magazine copy again.)
Drawbacks: 1/2 zip is lighter but not as versatile in warmer weather, hood drawcord needs some redesign, tapered cut won't fit everyone, slightly heavier than advertised 16oz vs 18.4oz, when I first got the bag there were numerous loose threads that needed trimming as if the seamstress didn't finish the job