I've got a Decked system in my Frontier long bed and my advice is that the two systems are very different animals. The Decked system is drawers, that can be subdivided for organization. It also has a lot of wasted space for the drawer mechanism. On a postive note, everything can be easily accessed and organized. Shifting loads is not a problem. Getting at stuff in the middle/front of the bed is easy because when the drawers are open you can be standing at the tailgate on the ground and reach anything along the whole length of the drawer.
I don't have a Diamondback, but from what I can tell from the website you likely have more usable space, because the entire bed is available for cargo. However, I would imagine load shifting would be a nightmare, and would require some form of secondary organization i.e., bins, bags, etc. under the cover. Looks like you have lots of hatches to get at stuff, but you are reaching over the bed rail into a compartment. Getting at stuff in the center of the bed would be a difficult reach from the ground with a lifted truck, in my opinion.
So bottom line, I think it depends upon your cargo and intended use of the vehicle. For me the drawers give me secure, weather resistant, highly organized storage at the cost of some storage space, and extra weight. YMMV