A good down alternative will perfectly mimic the qualities of real down to make the comforter very light and trap plenty of air. This means you will get all the positive qualities that real down provides you with without any of the detracting features like a bad smell and stray feather quills. However, the main sell for a down alternative is that it is suitable for those with allergies, so you don’t have to be left out of the comfort club if you have some sensitivities.