DimsonSomeone can correct me if I'm wrong, but I'm under the impression that the bottom of this sleeping bag is basically uninsulated, so it probably has 1/3 less insulation than a full sleeping bag.
OneSmallStep@Dimson OneSmallStep is right. The center of the back does not have down in it. The logic being, if it is compressed under your back or chest, it won't actually insulate. We removed that fill to save weight and cost.
We are psyched about the price of this bag and all the reviews have been incredibly positive so if there is a catch, no one has told me yet.
rcbellThere is no catch. I got the 20 degree bag on the last drop. It's awesome! Beats the pants off of any mummy bag I've ever been in. My quilt will still be my go to but this will be my below 35 degree bag. It's REALLY REALLY nice! The foot vent is a dream.
MikeGilbertThere is a bit of a catch. Unlrss you are buying the long version you will not be able to use this with a 25inch sleeping pad. I find the 20 inchers impossibly narrow, with my elbiws always on the ground and below the level of my body, which is quite uncomfortable. Fortunately I always buy long pads and bags, though at 6ft I am technically still within the range of regular.
We are psyched about the price of this bag and all the reviews have been incredibly positive so if there is a catch, no one has told me yet.