I was following the conversation and wanted to chime in. As an avid backcountry snowboarder I have spent many winter nights on the Inertia X frame, which is my favorite Klymit UL pad. My sleep system for 0 degrees Fahrenheit is a Sierra Designs Vapor Zero, Gossamer Gear 1/8th, and an X Frame. I place the GG thinlite against the ground to break up any direct conduction, place the X Frame on top of that, with my sleeping bag in the classic configuration on top of the X Frame. I have found this to be the warmest configuration, using gravity to get the most of the loft pockets. For a point of reference I am 6'5", 210, and am an active side sleeper.
I also use a Klymit Cush seat/pillow in a half circle shape and zip it tight inside my head section of my mummy. By doing so I add a ton of warmth to the head section, and can sleep well on odd objects like my shoes covered by a jacket.
I have slept on the X Frame in snow buried UL shelters at -20. The only additional item that I use at those temps is an MLD Spirit 45 quilt with Event at the head and feet. Temps vary so much at elevation in the Wasatch I always have this with me.
Almost everyone is surprised by the warmth of the X Frame at extreme temperatures. Special Operations Dev Group, the product testers for the military had nothing but positive things to say after sleeping on the X Frame at -60. Well, that is not true, their bulb pump froze and cracked, so we went and sourced a lighter pump that works well below those temps. OK, now my conscience is clear. The irony is most of our customers who buy the X Frame and X lite elect not to use the pump. I know I like mine super soft, but that is the beauty of the pressure point body map: at very low levels of inflation all air pressure is focused on your body contact points.
Our pads have been used on Everest, Denali, Aconcagua, Cerro Torre, the South Pole, and in some very cold, gnarly places. Candidly, I was more than surprised at the effectiveness of the loft pockets the first time I tried the X Frame, so I understand the reticence to giving the Klymit pads a go in the winter.
I just wanted to let you know what our winter camping experiences have been. I would challenge you to form your own opinion and test the loft pocket technology in cold weather for yourselves. Either way, happy trails!!!!