I do wear a stocking hat with my quilt buy also had to wear it with the mummy as tightening a hood made it much worse when moving around. I'd disagree with the thermal efficiency vs total weight issue since a quilt does not have zippers and draft tube, etc. So I think the weight of a 15 degree mummy is not lighter than a 15 degree quilt with the same down quality. I think we are not talking a lot of weight either way. Conceptually, I agree heating less space is required in a mummy because it's so tight but I think the down underneath you, zippers and draft tube in a mummy is basically wasted weight. Both systems require an insulated pad for colder weather so no difference there. Assuming both are comfortable at the same temps, I'd rather be comfortable and sleep good, rather than be comfortable and not sleep well. Not saying mummies aren't good for some but for those of us that move around a lot, a quilt is a great option and I was rather skeptical before I tried one.