personally i cant stand the norseman, i think its ugly. very very ugly. and i never understood the appeal, it's just not very interesting across the board. ugliest blade ive ever seen, and just a mspaint texturing slapped across the plain slab scales. boring, uninspired. okay boring might be a bit disingenuous but regardless, i really dont like it lol
the arius is an amazing knife, and so is the shiro. you really cannot go wrong with either. personally, i am partial to shiro. the shiros feel like a state of the art modern supercar, and the arius feels like a 1966 mustang. choose which one appeals to you more. if warranty is a concern, go with koenig. if you want a knife that feels like a space ship, get the shiro. another thing about shiro is they are the absolute kings of fitting the absolutely biggest blade they can into the smallest handle they can. so while it might be an almost 4 inch long blade, it carries more like a normal 3.5in knife. the f3 is my favorite model, f95 second. shiros also have all sorts of little easter eggs and treats integrated into them. little logos for the bearing style inside the handle, texturing in areas you would never look at. i love the arius, but shiros are just on another level of detail. to be honest nothing else comes close to a shiro, it feels truly special. arius has more of a drop shut free moving action, shiros are infamous for glassy smooth hydraulic action. i dont even like detent ramps but shiros have them, executed better than anything else on the market. so smooth you cant even feel the transition to the detent ball. i know koenig does good heat treat but no one does better than shiro on a production knives. shiro is doing custom individual blade heat treats on all their production knives. not 5-10 at a time, not 20, not 50. one. at. a. time. they never fall outside the optimal range. ever.
note how much more edge the shiros have yet how much more sleek and easier carrying than the arius. the handles are all of similar or equal length, yet the shiro fits a significantly longer blade inside. its more slender overall so it carries much better.
these are all keepers in my collection. i will never not have an arius, f3, and f95 of some kind. amazing knives all three. i just think shiro's are better if i had to choose.