In a sleep system with horizontal baffles, the fill tends to fall from the top, down to the sides through the night, leaving the top (where the most heat tends to collect) relatively uninsulated. Vertical baffles fix this problem by putting the baffles opposite the force of gravity but can create another. A full length vertical baffle extending from head to foot is quite a large space where down can easily settle in one end or the other unless the user is very diligent about redistributing it on a regular basis. My solution is a vertical baffle grid system that separates the upper and lower vertical baffes sections so that you get the best down control possible. No falling to the sides and no bunching in one end or the other.