Ask Sharon if you can get a sample piece of the poly. Next time I go there I'll check out each batting they sell by the roll. There are usually big bins of it up front in all different yardage amounts. There is no name brand on any of it that I have noticed just content.
I remember one time Marshall's gave our guild a roll of poly batting and we used it for tie quilts. It was fine. I have no idea the weight of it though.