That is like deciding whether a Ferrari or Humvee is better: it mostly depends on what you want to do with it.
The Military has more cutting edge, a slimmer blade, a narrower profile in the pocket and is much lighter. It is an extraordinary slicer, and is capable of taking on a wide range of tasks, from kitchen to campfire. Plus it is light enough to forget you have it in your pocket.
The Manix is more robust, has a wider blade, takes up more pocket space, has a stronger and more lefty friendly lock and is quite a bit heavier. It is also a confidence inspiring knife that feels in the hand like it can take whatever you can dish out. In side by side cutting tests, it has out-perfomed knives costing twice as much.
The ParaMilitary is also lightweight but very strong, with a different lock (between the Manix mid-lock and Military liner lock in strength). The inch shorter blade makes it less threatening to use around NKP, and a bit handier to use for fine work since the finger choil and shorter blade get your fingers closer to the tip.
Of couse, there is also the Mini-Manix to consider. Some people prefer the ergonomics of the 83mm Mini to its big brother. It has the same kind of heft and tank-like feel as the Manix, with the shorter and somewhat friendlier leaf-shaped blade, and the four-way clip option as well.
Now that I have thoroughly clouded the issue, welcome to the forum
