I took this bivy on the Colorado Trail this summer and LOVED my choice. I had a very limited time window to complete the trail and was alone, so it was absolutely perfect for me. I am 5’10” and slim, used a OV mummy pad and a 30 degree EE Enigma, and had no problems with filling the bivy up even when on my side. If necessary I could pull all my gear inside in the head space, which made it pretty tight, but more often I left my pack and shoes outside in a compactor bag. It was light and small in my pack, waterproof in the rain, allowed me to watch the stars (probably my favorite feature), and allowed me to hike much later into the day, not worrying about finding a good campsite or having enough light- as long as I wasn’t on the side of a cliff, I could find a spot to set up. In the mornings I could unzip, set up my stove and make a hot breakfast while my always cold toes were still cozy in my bag, then pack up in a matter of a minute or two and hit the trail. Loved it! Disadvantages were: basically no living space if there’s precipitation, no room for a dog. Otherwise, a perfect shelter for this trip and for solo trips to come!
Stargazing from 12,000 ft up can’t be beat, especially when all you have to do if it starts raining on you is a simple zip. I can’t think of another fully waterproof, one pound backpacking shelter that lets you see the whole night sky.