I have a lightweight hypo-allergenic polyester filled quilt with pure cotton cover. It is all I have ever needed in winter here in the tropics.And then I only require it for a couple of months.THIS year I have not even needed it once yet!
I use a lambswool one all year. If it gets really cold we just put a mink blanket over the sheet and it keeps the bed super toasty and soft. The lambswool ones are excellent for allergies and I've found that even when I wash and tumble dry them they never go lumpy.
We have donnas filled with duck feathers, hand sown by a Chinese man in Sydney, where I live.
That was many years ago now, & we had them dry cleaned & picked them up a few months later, 1 of them had been handed to someone else, by mistake,& we now have their 1. Luckily theres was also filled with duck feathers, but it had been sown differently.