I absolutely love duvet's.
The one I have on my bed at home is a down duvet bought ~ 10 yrs ago, on sale for $500+. It is truly amazing.
When I lived in a colder clime, it kept me warm. Now that I am in a warm clime, it keeps me cool. It is very thick but very light.
My boyfriend was so amazed with it that the one time I was going to his place for a week, he asked me to bring it. Um yeah, I did that alright