Erin B.wrote a review of Arc'teryx Atom LT Jacket - Women's on December 1, 2010
The fit is perfect- tailoured enough to look good when wearing on its own and to wear under a shell, but still enough room for additional layers underneath. The cuffs are also great- made from elasticized material that stops any cold air from seeping in when raising your arms.
Very warm. Down to -5C or so, I wear it around without a shell and am happy. For colder/wetter conditions, my gore tex shell comes on top. And so light! People constantly wonder how something so thin and light is warm, but somehow it is. It is nice to wear something that doesn't look or feel bulky but still be warm.
Breathability seems good, but haven't yet tested it under extreme conditions ie ice climbing. Water resistant against light rain.
I choose the non-hooded version because I planned to wear it under a shell during the winter anyway, in which case an additional hood would just be irritating. Also because I read that the hood was (unusual for arcteryx) ill-fitting.
I read that there is a drawcord on the atom lt hoody- this would be a nice improvement to the atom lt.