Warmth – ExLight vs. Arcteryx Cerium SL

Also -if anyone's used the SL/Exlight, which do you find it sweats up faster?

Not an answer (sorry), but my warmth has more to do with what I had for dinner than +/- a couple ounces of down. This is one area where the more important differences are durability of the shell, initial cost, and how sustainable the manufacturing practices of the companies are.

I've owned both the EX Light and the Plamsa 1000. The 1000 fill power sounds like a gimmick, but the jacket is worth it IMO over the EX light because the EX light is curiously short. I think Montbell cheated at the time to build the lightest down jacket in the world by making it so short. Or maybe it's just a Japanese style. The Plasma is lighter by .8oz and longer by about two inches, but more expensive. It has .2oz less down fill but also ~11% more theoretical loft per ounce from 1000 fill down. Not to start a debate about how good 1000 fill down is in practice. They both have the same 7D fabric and same style thin zipper. But it's still less expensive than the Arc'Teryx jacket.

My point is I think you should compare the Plasma 1000 and the Cerium SL.

I have the SV version of the Arcteryx and it is much, much warmer. I have had it down to -15C and it was suitably warm at that temp (wearing a long sleeve merino 100 wt shirt. The insulation is heavier where you need it. Honestly, it surprised me at how warm it was for the weight.

The MB was much too short and had about half the visual loft.

I have the free time. So here’s the OPs latest try on the dead bird jacket. Includes trolls

mudslinging

I am ashamed of you, Ken Thompson.