Arc'teryx describe the Fission SV, one of their top of the range garments, in this way:
"Maximum warmth in a GORE-TEX® garment that is waterproof, windproof, durable. New GORE-TEX® face fabric has a softer touch and moves quietly. Reinforced panels in the hood and across the shoulders, chest area and sleeves address areas of high use and sustained abrasion. Lightweight, radiant Coreloft™ insulation is stitched into place and delivers exceptional warmth that is almost weightless. Lighter weight insulation is used in the underarm gusset to reduce bulk and aid with ease of motion."
They love it. It means the world to them - this is a special piece and they're proud of it. Do I agree? Well that depends on what use it is put to. It's not a trekking piece to my mind - at least not the way I trek. I prefer to layer rather than to have a single unit doing all the work with the exception, perhaps, of the Buffalo Special 6 on local hills (we're talking pimples really - Leith Hill in Surrey is hardly likely to have Mountain Rescue coming out, but as I will post shortly, I did spend some time with Lowland Rescue recently). But, for sunday afternoon walks, doing stuff out in hard, cold weather and the like, it is great. It really comes into its own for winter sports. Skiing, snowboarding, dog-sledding (as above) - this is the perfect jacket for all of that. A down jacket will pack smaller than this but will be nowhere near as durable, versatile and easy to use.
What about features? It's gore-tex so waterproof and breathable, as much as that means at the current level of technology. I'm not going to enter a debate about waterproofness vs breathability - we all know the trade-offs. This range of gore-tex is getting rave reviews and is worth a try instead of eVent and Neoshell. More so than ever before. The construction of the jacket is designed to reduce bulk - seams, stitching, it's all meant to make the jacket less of a bruiser. Drawcords are adjustable with one hand and with gloves on. Elbows are articulated. The zips are Arc'teryx waterproof zips and have garages to protect from snow (and rain) ingress. The chin guard is laminated and smooth as fleece.
The collar is insulated, so is the hood. And it's all helmet compatible. Cuffs are velcro adjusted and easy to use with gloves. The hem drops down below the butt (so you can sit on cold ground, and is adjustable. However, the waist is not and here Arc'teryx have missed a trick. The cut is expedition cut which means it comes up big - it's built that way to allow other layers underneath should you need them. I would have liked an adjustable waist to bring it in.
There are six pockets - two hand, two chest and two internal mesh. These last are useful if you want to stow lightweight things in there like a hat or gloves and which would benefit from being close to your body. Insulation is a serious business and 100gsm, and 140gsm, Coreloft means business. This jacket is very warm. As I have said, I used it in -20C and did not feel the pinch. It's easy to care for too - machine wash in warm water without fabric softener. Can you say that about down?
All in all this is a class jacket for the right activities. It breaths well through all that core loft but high-intensity activities are going to make you sweat. You cannot expect moisture to simply evaporate through all that fabric and insulation without some remaining nearby. But I doubt anything else will beat it. It's user-friendly too. A couple of changes here and there - perhaps some larger toggles on the zips, an adjustable drawcord at the waist - but in reality these are small points but perhaps, for the money you're paying, they are good points to consider. Arc'teryx pay attention to this blog apparently, so comment away and they'll pick them up.