Hi,
I am looking at -40 sleeping bags for a Denali trip this May as well as for future use in the Himalaya (I sleep a bit cold and my -20 bag has done me well for Sierra stuff and South America, but I know I'd be cold in Alaska or Himalaya with it).
I suppose I have it narrowed down to the Marmot CWM, Western Mountaineering Bison, and Feathered Friends Snowy Owl. They're all mighty expensive and all have same temp ratings and similar down fill weights, so for me it will come down to compression.
Does anyone have any perspective on how these (or other -40 bags) compress relative to one another? If no difference, then I might as well go for the cheaper Marmot Cwm bag. But if the WM or FF offered greater compression or other advantages, I may be tempted to go for them.
Any help you can provide to help me make my choice is greatly appreciated!
Jason