The "trampoline" suspension used with some of the Osprey packs has much the same issue as do packs that use lightweight sleeping pads as part of the suspension. Both systems put a fairly thick layer of lightweight material between the heavy part of the load and the users back. With the Osprey packs this is a "layer" of air: with packs such as the SMD Starlite it is a layer of sleeping pad. With a light load this is not much of a problem but as the pack weight increases it creates more leverage against your shoulders. Some people don't mind this "cantilever" effect; others, myself included, find it uncomfortable ( eg. Sore shoulders). In fact, I now use a single layer of CCF in the pad pocket of my Starlite and carry my sleeping pad on one side of the pack to minimize this cantilevering. So, IMO, you are faced with a potential trade off between sore shoulders and a sweaty back.