I went with a bivy in Wyoming, about 10000 feet for muley's, so I figured i'd take my chances with bad weather and take a bivy, I can live with frozen gear and boots the next morning, I could'nt live with waking up 20 times in one night shivering, because the OR gore-tex alpine bivy, I was in was supposed to reasonably manage moisture, this was not the case at all, 15* Marmot Helium bag soaked, miserable night. Zipper open the 6" for ventilation, didnt do much. Luckily for me the next day was just windy and cold, no precipitation. So I could dry out my bag, and not have to head back to the truck. Even the nights without the snow, which allowed me to keep the bag completely open, I'd still have bad condensation issues. Maybe, if I didnt have a down bag it'd been better, but then I'm not saving any weight. I'm selling my OR Alpline, and buying a good solo tent this year.