I've had a couple of Arcteryx Alpha SVs over the years and this year I decided to go with an Atom SV Hoody in the same size. I already have an Atom LT Hoody, but for winter I wanted a little more insulation. I also have a number of other Arcteryx pieces and like them a lot.
Out of the bag, the Atom SV Hoody looked great--just as it should. Then I put on the Alpha SV shell on over the Atom SV Hoody and zipped in. I'm just over 6', weigh 155 lbs. and the size small Alpha SV shell is perfect. Unfortunately, when I put on Alpha SV shell, the hem length at the front of the hoody was an inch or two longer than the shell. The rear hem of the hoody was cut correctly and was under the hem of the shell. Very disappointed although it's probably just a production error, but I'm surprised at the lack of quality control at Arcteryx. Otherwise the Atom SV Hoody is a great jacket. Warm, toasty, made with coreloft, great sleeve length, hood fits nicely under a helmet (use a beanie otherwise) and it's a substantial upgrade in warmth from the Atom LT Hoody, by 100 grams. I'll revisit my review when I hear from Arcteryx.... Then I may change the number of stars I've given this hoody. With the exception of the too long front hem, the jacket fits true to size. But I don't want to wear something that may be wicking water and you would think that Arcteryx would be more careful!
Called Arcteryx and they said yup, the front hem of the Atom SV Hoody is longer than the front hem of the Alpha SV shell. They said they had down options but not synthetic. Living in the Pacific NW I totally prefer synthetic because it's often raining and windy where I hike in the Cascades rather than snowy. Gearheads at Backcountry suggested the Arcteryx Nuclei--warmer than the Atom LT and fits under the Alpha SV shell perfectly just as the Atom LT. Thanks Backcountry!