have only used sleeping bags, so I am curious-re weight, wouldnt the only difference be the zipper weight? I agree that mummy bags can be constraining, but I see how opening or closing a zipper more or less is less convenient than various opening options of a quilt? Dont you find that your feet tend to stick out from moving out when asleep, or arms or whatever?
Ive never seen anyone use a quilt in my years camping, so while I know how they work at home in a bed, I do wonder about the stated advantages. I do see the disadvantage of waking up cold if your leg or whatever sticks out, or if in turning, you end up not wrapped up--more for cold nights I mean.
Do you use a quilt, doona or duvet at home?
We do, a queen double, of course, but the real beauty of a Q/D/D for me is that I can throw it off to cool down, or "roll up" with it if I am cold. My legs act as very good heat moderators. I do the same with the duvet at home and have been doing this more and more with my down sleeping bags. I also spread my leg and arms a lot more, and I also find bags confining and eventually annoying.
As to weight, I am not sure because I haven't got anything to compare, and much will depend on the down content and area that the quilt covers.