I too want to chime in. I used my 3 season one in 30* weather-it worked FANTASTICALLY. Great quality, quick to ship, I highly recommend picking one of these up. I initially thought it would be too short, and my legs/feet would get cold, but that never happened (feet were in the footbox of the sleeping bag). the sides come up nicely over the shoulders. A little tweaking on my end,and had a great night out with it in below freezing temps.