Just about any batting can beard. The worst are usually wool or polyester, but it is not unknown for cotton batting to beard. The Hobbs Poly-Down is treated to prevent bearding, but this is not a guarantee that it won't beard. Much depends on the backing fabric used, the size of the needle, the strength of the machine "punching" the needle through the quilt sandwich, etc.
Do you have a quilt with a black fabric backing? If so, will you be machine quilting it on a longarm or on a domestic sewing machine? Is the fabric batik, or regular quilting cotton, or.....
What would be your reason for preferring Poly-Down to the Hobbs 80/20 black batting? The reasons I can think of would be that you want a higher loft and/or faster drying time for the quilt. If so, you have to weigh your reasons for wanting Poly-Down against your reasons for using the black batting (with primary reason being security so that, if the batting does beard through the black batting, it won't show).