I use a Eberlestock J107 Dragonfly, and like it. It has an adjustable suspension system, so you can tailor it to your torso size and comfort. Like Idaho Sawyer mentioned, a pack that will hold up to a heavy load isn't going to be ultra light unloaded in the first place. I have hauled out elk quarters and heads with no issues other than being exhausted from the hike afterwards.
Eberlestock's motto is "Go in light, come out heavy" While this pack is good for that, I often joke with my buddy that I "go in heavy, and come out heavier" when using my back for backpack hunts. In other words, there is lots of room to pack stuff, some gear that isn't even really necessary
. The detachable fanny pack is nice for ditching your gear and just taking the essentials when going on a stalk.The only thing I wish the 107 had was some internal organizational pockets for smaller items such as knives, gps, calls etc.