Okay, this is a nit, but the sleeve on the Agnes adds an un-necesary layer of fabric that adds a littleweight.
I made my own that has no un-necesary layer so it weighs a tiny bit less. I sleep directly on my mattress, but don't find any problem. An extra layer of fabric may be worse - you may slide around more?
The Thermarest Haven has a funky open bottom so you need a groundcloth - extra weight. But, I think that actually works pretty good. I think it was reviewed at backpackgeartest.org.
I would call it a quilt/bivy hybrid, not quilt/sleeping bag.
I think this alleviates the big problem with a quilt - that air can get in the sides.
On the other hand, there can be an open space on your sides that reduces warmth.
And you need to have a flap at the top, over your shoulders, to prevent air from blowing in/out there. I don't know what the Agnes does. With the Haven, it's like a sleeping bag at your shoulders so there aren;t any drafts.