Comforter help and tips
If you're getting a down comforter, make sure the quilting (stitching) goes across the comforter in both directions, making squares. My comforter is stitched lenghwise only and the feathers collect at the bottom. I also made a cover for it out of sheets I got on sale at Wal-Mart. I toss the cover in the wash when I fluff the feathers back to the middle of the comforter. When I have to wash the comforter, I do so at the laudromat and use the extra huge washer. I tried using my washer at home, but it was too heavy after it got wet. I scorched part of it in the dryer because it didn't rotate properly and pieces stayed against the hot dryer wall too long. I love my comforter and have had it for 20 years. The payback has been in the thousands of dollars ( I live in California and you know about us and electricity!) saved in nightime heating bills.
The percentage down versus feathers. A duvet that is all
down will be hideously expensive. The cover needs to be extremely
tightly-woven or the down/feathers will poke through eventually.
The stitching needs to be even and the duvet divided up into sections.
Otherwise the down/feathers will shift and result in cold spots.
Your capacity for washing it or having it cleaned. Not cheap either
way. A down duvet that stays unwashed/uncleaned gets heavily allergenic
quite quickly. If you do get one, get a duvet cover at the same
time. This can be removed and washed every week. Not much point
in getting a down duvet otherwise.
Quite honestly a good polyester one will be just as warm and
quite a bit cheaper. Easier to wash and less allergenic.
Polyester-filled duvets are inherently less allergenic than down duvets. The feathers/down break down over time no matter how carefully cleaned. The filling is also an absolute heaven for dust mites, as there isn't much difference chemically between down or skin. There are dust-mite proof covers available, but perhaps these aren't so readily available in the US either.