The raptor's nice but it's still just foam (with ridges in it and mesh on top) touching your back. The marmot (and i think the other osprey, though I haven't tried it) actually has a suspension with aluminium stays that keeps most of the pack completely off your back so air can circulate even when cinched down. Plus it has more storage, I'm not sure if even the largest raptor pack is large enough for a commuter at only 18 liters.