I’m not looking to annoy anyone here, the the worst warmth to weight ratio bag I’ve ever owned is by nanok. Might just be that model though.
I bought a snugpak about 15 years ago for summer use “in case it might get wet”. It still hasn’t, mainly because of using a Ortleib dry sack to stuff it into. It’s had hundreds of uses, been washed and retained its insulation value, and generally been the cockroach of the sleeping bag world. I wish it would die so I could get myself a down bag.
Snugpak are among the best synthetics, but I’d go down and a waterproof stuff sack.
(Brands owned and used Snugpak, Nanok, North Face and Ajunglak (spl?))