A couple of years ago I was looking for a light-weight insulated jacket that was breathable as well. After searching for a bit, I found the Arc'teryx Atom LT.
Originally I bought the Arc'teryx Atom LT Jacket LEAF, and a few months ago the Arc'teryx Atom LT Hoody.
The LEAF Jacket and the production hoody are essentially the same in terms fabrics and materials. Made with Gossamera fabric on the chest and back, Polartec Power Stretch fabric with Hardface (added wind resistance, breathability and durability) technology on the side panels and light-weight Coreloft insulation (60g/m²), these jackets are warm, breathable and light weight.
These jacket are designed with movement in mind. The fabric is less noisy than other jackets I own and the slighly longer back really helps keeping the coverage of the lower back when you are kneeling or climbing.
The fit is trim, very sporty. It layers well under heavier jackets (so it can be used as a mid-layer as well) and the fit also allows for good, confortable wear under a backpack or plate-carrier.
The cuff are simple, no velcro or other type of closing, just a little elastic. But they work and they work very well. They lay flat as well, so if you are wearing gloves they slide nicely inside their cuff.
There are some differences in the insides of the jackets, the LEAF version from 2012 and the Hoody from 2014, but they are essentially the same. You can see the side panels above (and in the picture below). These panels not only help with the movement, but they provide a lot of breathability and lower the bulk of the jacket. The Polartec Power Stretch is really a good fabric.
Of course the LEAF version has no reflective logos, like the Hoody. The LEAF Jacket fit a little trimmer than the production Hoody, but maybe this is due to the difference in years of making. I don't know. I've seen the LEAF Hoody and it seems pretty much the same as the production.
The only issue I've had with either jacket is the zipper on the LEAF version. After a little over two years of wear, the zipper is a bit loose. What I mean is that if you are running, climbing, or generally moving, the zipper pull will slide down, slowly but surely and you will have the jacket opened and flapping in no time. I haven't seen this with the Hoody, but I haven't had it for long enough to be able to compare this properly.
Both jackets have an internal pocket as well as two hand-warming pockets outside. The zipper pulls are standard and they are holding OK.
Overall I've worn this jackets on lazy sunday days going to a cafe and outside, either climbing on the cold New England winters or on projects with the Team.
the fact that I bought two should tell you that I really like and trust these jackets.