As for big loads (60+ lbs.), what I found with the Aether 85 is that the shoulder padding would deform and twist slightly around the main load-bearing part of the strap, leading to, um... let's say, a certain amount of discomfort. It seemed to me that was the only limiting factor in the Aether's ability to handle the weight. So I called Osprey and learned the straps are interchangeable with the Argon's. Since changing the straps I haven't had the pleasure of carrying quite that much weight, but under more reasonable loads I can already tell it's a whole lot better, and very comfortable.
