The only difference between the comforters is that the PureDelight (Ultimate) is filled with white down whereas the PureComfort is filled with gray down. Down can vary in color, from white to gray depending on the breed of the bird and the season in which it was harvested. The color of down does not affect its thermal characteristics – a gray down will insulate just as well as a white down of the same size cluster and maturity. Even the cover material is the same: close weave 100% sateen cotton. They are both super lightweight, and cloudlike. You will love either one you choose.