Since one commenter noted the hood, it's worth pointing out that the Atom comes in 4 forms: The LT jacket, the MX jacket, the lt hoody and the sv hoody. The MX jacket has polartec panels that extend up the sleeves, the SV jacket has more insulation, and the hoody has....you guessed it, a hood.
The breathability of the Atom's face fabric impressed me. I would rate the breathability of this piece higher than your average sweater-weight down jacket, with comparable warmth and less cold-spots because there are no baffles.
Also, the use of fleece under the arms (except on the SV) adds a lot of stretch and extra breathability. Great pieces!