I just picked one up. I have an older Tool Box that has served me well, but wanted a bit more space when packing in a pile of cold weather gear for an all day sit. I haven't loaded up my Hawk Stand yet to see how it carries etc ...
I was leaning towards the Cargo Box as I like the layout / pockets and the Tool Box design is a winner IMHO. I did look at the Mystery Ranch / Stone Glacier / Kifaru options hard before deciding on the Cargo Box.
The pockets / bucket design with how it hangs and still allows for the pack to have a bunch of gear in it, ability to attach a stand and about any combination of Climbing Sticks, Rattling Antlers, Extra Clothing, 32 ox Nalgene (while still having room for a Thermos inside (never underestimate the comfort from Warm Coffee / Soup on a cold day!)).
I don't feel like my WT pack needs to be awesome at carry heavy weight as I'm dragging deer out. The worst case is a stand + sticks and this pack should do this well based upon the design. I thought hard about some of the others as they would be better all around packs (which is true), but all left me wanting key things for WT season and I do have a couple of Kifaru packs for those purposes anyway ...
I bought the cargo box after trying to find out online if it would carry the summit viper comfortably, without having much luck. I risked it, and bought it anyway, and I'm happy to say, It carries it very well. It's definitely bulky with such a large stand on your back, but honestly I had no idea that stand could be carried that comfortably. I would absolutely recommend the cargo box. Plenty of organization, and the loop for hanging it from a tree works very nicely.