When my oldest son went to college 8 yrs ago, he challenged me to make a down filled quilt to take with him. I wanted to make a duvet but he nixed that idea. I ended up using a full size down comforter as the batting for his quilt. The bargello in my avatar is his younger brother's college quilt and it was done the same way.
They are the only two quilts I've done this way. Quite frankly, it's a pain in the rear end. The quilts are very heavy and were a nightmare to get through my machine arm. Plus, because down is so fluid, to make it work right under the quilt, I chose to remove the comforter baffle stitches one section at a time before I quilted that section. I had to remove the stitches, pin a small section, quilt, and repeat over and over....yep, what a pain.
HOWEVER, the finished results were remarkable. My boys absolutely LOVE them and actually showed them off. To have a teenage boy say "LOOK at what my Mom made for me!" is a wonderful thing. Not fun to do but well worth the effort!
Oh yes...Because I used washable down comforters, they're easily cleaned with no problem. The oldest quilt is just over 8 yrs and the other is about 5. They've been heavily used and washed several times and are in great condition.