This insulation was first introduced in 1991 and was tested against goose down (80/20, aka 595 fill, was best available at the time) by an independent lab. I have a copy of their test report and it says in part, "...The 100% milkweed did not perform satisfactorily as a loose fill material. It was rated significantly rougher and lumpier than any other fill material, was significantly thinner (less lofty) than 100% down (although matched on a per unit weight basis), was the least compressible of the loose fill materials, and had the lowest insulation value of the loose fills. Furthermore, cleaning significantly affected the 100% milkweed fill; it became very matted and lumpy after cleaning, decreasing significantly in thickness, compressibility, and insulation value. The decreased thickness after cleaning corresponds with its considerable decrease in insulative value after cleaning. Therefore, we cannot recommend 100% milkweed as a loose fill material...."
The valid market for this material is to mix with down for lower cost mass market insulation. On the negative side, it will not make you pack lighter. On the plus side, it will not make your wallet lighter if you want to stuff your home pillow with the mix.