I purchased a used DOC/Elmax here for $256, mostly because I was interested in the design and because I like Elmax steel. The fit and finish are good. It's a big knife with a big, shovel-like blade with the nightmare grind. The lockup is incredibly solid.
The flipper is not easy to open. By comparison, my ZT0560CBCF flips open easily. There is no blade play on my ZT, but the DOC feels more solid. While the fit and finish of the DOC are very good, the fit and finish of the ZT are awesome.
Neither of these knives are slicers. The blades are thick and brutish. Both have thick tips, making detail work difficult. The ZT, after being reprofiled to 30 degrees inclusive, has a edge shoulder that's 0.0390 inches -- very thick. The DOC, which I have not yet reprofiled, has edge shoulders 0.0220 inches wide.
The blade on the DOC has that weird nightmare grind. I haven't yet found any use for it, but it does make the blade very thick mid-blade about an inch back from the tip. I measured the blade 0.1630 inches. At a comparable spot on the ZT, the thickness was 0.1125.
The strange grind on the DOC can lead to asymmetrical cutting in some media. I used the DOC to cut open the hard plastic shell of my printer cartridges, and the grind caused the blade to veer into the cartridges, fortunately without damage.
I like both of these knives, but they make poor EDCs, unless you need a truly beefy blade for extreme hard use. The Military will cut circles around both of these knives. Nonetheless, I love having both of them in my collection of users.