I had to look up doona, MsOlga .
Outside of Australia, it's called a comforter or duvet
I am a semi-allergy sufferer and given that we have in southern California
more warm days as cold ones, I opted for synthetic fiber. It's just easier to clean
and inexpensive, which translates to buying a new one more often.
I do have all natural fibers (cotton) as duvet covers though. I also use a wool
blanket on top of the duvet, should it get really cold in the winter (seldom).
Dto. for pillows: synthetic and frequently replaced.
For our climate, I would never use down or feathers. Wool and cotton definitely, but as I said, I'd rather replace the bedding more often and synthetics are easier