Understanding the difference between a comforter and a duvet is important for those who want a really fluffy bed cover. A comforter is much like a quilt, except with more filling that is a little fluffier. The comforter filling is usually cotton batting or a polyester blend. On the other hand, a duvet is filled with natural down, feathers from geese. It is no wonder a duvet is warmer and fluffier than a comforter. For a really puffed up and luxurious top cover, the duvet is the best choice, although probably the most expensive choice. Whether the top cover is a big heavy comforter or a down filled duvet, the appearance of the outer shell can be changed for the season with a holiday duvet cover.