Bed Comforter A great alternative to a blanket is to top your bed with a comforter. Comforters may be filled with down, wool, cotton or polyester fibers. They tend to be puffier than a blanket and high quality down filled comforters are also much lighter thanks to high fill power. To learn more about down and fill power, read our Understanding Down Bedding page. To learn about the benefits of wool, read our What's Great About Wool page. Both types of fills have unique advantages.