I’m experimenting with a quilt right now because I found a pretty good deal on a used Warbonnet Mamba XL 20deg, and because I found that I tend to unzip my bags and lay them over me like a quilt anyway—as long as the temps aren’t pushing the ratings.
But even with the XL version, I get a lot of drafts. I toss and turn a bit, and it just seems like there’s no way to go from back to side without lifting one side of the quilt. If I tie the quilt under me, it’s great for back sleeping but I get massive drafts when I roll. If I use some shock cord and run it under my sleeping pad, I can keep the drafts out when side sleeping, but it pulls kind of tight on my top shoulder, flattening the down and lowering the temp rating.
I think I’ve decided to stick with a bag when on the ground and pair my top quilt with an under quilt for my hammock.