I have a Snugpak Chrylsalis. I have yet to test it in extreme conditions. It is rated to a low of 20 degrees, but have only had it down to 40. Being a very wamr sleeper I was actually fine in the bag, so it might not be good for everyone at that temp range. It does handle condensation very well, no dampness at all in the morning. I'll try to let you know if I get a chance to really give it a workout anytime soon. It is very light and compressable, and doesn't really seem to have much loft, or need it <img src="/forums/images/graemlins/smile.gif" alt="" />