I decided to go with the OR Helium Bivy for a number of reasons, but most importantly: the single, flexible hoop-pole that keeps the fabric away from your face. While it performed well in sub-freezing conditions not some regards--keeping out ground moisture despite being deployed directly on top of packed snow--I did have several issues. I wanted to keep the bivy fully closed to conserve heat on a 15Â°F night on the side of a mountain at 8500' but in a terrifying episode, I awoke in the middle of the night with pulse pounding, feeling as though I was suffocating. The problem was remedied by partially unzipping the bivy near my head, but with the internal heat gone, all the moisture from my breath froze to the internal walls and surfaces, leaving me and my gear soaked. I'm sure it performs great in above-freezing conditions (and it does come with a mesh closure), but in the future, I'll probably leave it zipped open and deal with my head/face being exposed to the elements so that my breath can vent properly, and I can get adequate oxygen.