nartreb wrote:There are differences between natural down and synthetic, but warmth isn't one of them.
Exactly my main point.
nartreb wrote:But if you already own a jacket that's warm enough (Corax says it is), you will be fine if you stick with the one you've got.
Under normal conditions the Ar'x jacket should fine.
What I don't really get when listening to discussions about warm clothing in the mountains is the fanaticism about down. Down is great, but there are other materials which suffice and also have advantages compared with down.
Another thing that makes me a bit curious (even mentioned in this thread) is that many climbers seems to have a set elevation limit when a certain type of clothing should be used. I've been above 7000 meters without down clothing, even summiting 6500 meter mountains in only a thermal underwear sweater without feeling cold, but I've also had hypothermia on very low peaks. It's all about the conditions. The jacket in question is definitely good enough for Mera Peak if the weather is normal, even on the rougher side, but no expedition clothing in the world will be enough if a violent fall storm hits.
Another important factor is what kind of a climber you are. Some are going on high frequency, with few or no stops. Others go slowly and take long breaks. It's huge difference. A friend of mine crossed the arctic, from Russia via the North Pole to Canada without any down clothing. He thought it was dead weight. He did bring a good down sleeping bag though.