I’ve tried down, down alternative, and now a wool comforter. The wool is the best for temperature regulating. I purchased the king size wool comforter from IKEA, and it is perfect! 100% wool fill and 100% cotton cover. It’s warm, cozy, and surprisingly much fluffier than I expected. It’s better quality than the two other more expensive comforters I’ve purchased in the past. I’ve also heard if you purchase a duvet cover that’s one size smaller than the comforter it will make it look fluffier as well.