I tried quite a few duck down comforters and didn't like them because they made me so hot. I like a big fluffy comforter, but I don't want to be hot. I already had a goose down comforter and found that even with the same warmth level and fill level as my duck down comforters, the goose down ones were always lighter, warm but not smothering. So that was the feature I was most worried about finding while I was looking for a King size - light, warm, but not suffocation hot. My old duck down comforter used to have me waking up in a sweat every night, but this one does not.
In terms of warmth, this comforter is true as advertised. It is light warmth. I would not even say it is all season, because it's very lightweight. I use it as a second comforter (I use this one and another "all season" goose down comforter) on my bed where it's 64 degrees- personally I don't find this warm enough to use by itself. However, if I do get hot, I can kick off my second comforter and this one doesn't make me sweat at all.
Currently this comforter is covering my Queen size bed and box spring on a four poster bed. My Queen size comforter didn't go all the way down the side of the bed and left the box spring visible. This one cover is up completely, so that's great.
Only disappointment is how flat this comforter is. For the fill weight, I thought it would be fluffier, but it's the same or less fluffy than my 550 fill weight one. However, I noticed that once I put this in a duvet cover (it does not have ties or snaps, I just safety-pin mine in), it seemed to fill out well and looks nice. Since I would NEVER recommend using a nice comforter without a duvet cover (why ruin your investment?), it works out well enough.
Lastly, wanted to mention the manufacturer's tag does say "WHITE GOOSE DOWN" and then 75% minimum down. For whatever reason, the packaging said it was duck down, but it's clearly goose down, both because the legal tag says so and because it doesn't have the heat-trapping suffocating warmth I associate with duck down.
