I purchased this bag and the Marmot Couloir. Off the bat, it would seem as though the degree rating may be off. The loft in comparison to the Couloir and other zero degree bags seems low. This is probably explained in the fill weight which is 2-3 oz less than the Couloir and other bags I reviewed (Mountain Hardwear Phantom & Banshee). That may not seem like much, but from comparing both bags it would seem to be a lot. Also, the bag is more then roomy. It is a cave. I felt like I could flip around in the bag (5'11" - 260lb). As someone else noted, I too worry about the excess space and how it would affect the bags efficiency. Laying in the bag felt like I was rolled up in a plastic tarp. It was very rough and not as silky at the Couloir. As you can tell, I am returning the Super Spiral Hugger and keeping the Couloir.