Do you sleep hot or cold?
I have a comforter that I love and have had for eight years so far. Fair warning, it's pretty spendy, and not sure I would buy it now that I've discovered mustachianism even though I fully anticipate keeping this for at least a few decades more. It's the bavarian down comforter in medium weight at Feathered Friends. Don't let the "medium" fool you, this thing keeps me SO WARM in winter, even with windows open.
My boyfriend, however, sleeps too warm for this. I have a lightweight down comforter from Snowe that I use in the summer and he uses that year-round when he stays over with me. Both seem relatively well-made, but I've only had the Snowe for two years. The Feathered Friends one has stayed very lofty and is a like-new hotel level of loft even today.