When I got the BWY mainsail handling system ( lazy jacks and stack pack) it converted my main to loose footed. I don’t know enough about sailing to comment on performance but it is supposed to be better. I would say the shape of the foot of the sail looks a little smoother. Todd at BWY commented that the advantage of loose footed was probably cancelled by the addition of the stack pack. I do love the system. Unzip, easy up then lowers into stack pack and zip up. No loose sail all over deck and awkward flaking.