I don’t have much experience with bivy bags as this is my first bag. I have camped many times in weather ranging from 30 degree to -35 degree Celsius overnight lows. I tested this bivy out during a Canadian winter in a shed at about -20 Celsius for the outside temperature. The shed had a wood burning stove, but it went out in the middle of the night. I wanted to test this bivy out in a situation that was safe. I used the bivy with a -15 degree bag, a thermo lite liner, a self inflating pad and a ridged foamy. It was very comfortable and I was warm for the night. I am tall at 6’8” and I am about the tallest person that would fit this bag. In the morning, there was wetness in the bivy and wetness on the exterior of my sleeping bag. I wiped it with a micro fibre towel and the amount was not excessive. I am looking forward to trying this bivy out again, probably in the spring where conditions aren’t as extreme. I am satisfied with my purchase and adventure gear had the best price and the shipping/delivery was a smooth process.