Gun blue is actually better than parking which was done because it was cheaper and you could do big batches. The story about the Springfield is an excellent example of the dangers of anecdotal evidence. The rust was probably caused by the fact that older guns have steel with much less chromium and alloys than modern guns not the bluing process.
Bluing is a rusting process, just controlled. If the chemicals are not rinsed and or neutralized the rusting process continues. Rust bluing (and Browning) require the parts be exposed to high humidity for up to several weeks and the rust is carded off.(wire brushed)
Park is a coating that clauses some amount of etching but actually builds up on the surface of the metal.
The advantage to Park is that it has pores/ a crystalline structure that will absorb and hold any oil or rust preventive. That is why it is the perfect sub straight for the paint finishes that were mentioned above. I would not Gun-Kote over bare metal that can be parkerised.
Caustic Blue, the industry standard and parkerising are applied in the same manner. The parts are cleaned and dipped. Bluing requires app. 100 deg. more heat. I park at 195
+ and bluing begins at 290-295. Niter blue requires heat as high as 700+.
Parts being parked will set in the tank about 5-7 minuets, Bluing can take 20+ for the desired Finish. Park is applied over a blasted Finish for the best bond and will hide a 180 grit blasted Finnish. Bluing can be applied to any grade of finish but will accent any flaws in the metal. A 600 grit sanded finish may shine but you will see the scratches in the proper light.
Any park finish is less reflective than the dullest blue finish.
Blue is much more sensitive to any oils on the parts being finished. Even the oils from your fingers can cause discolorations.
When a part is blued and oiled the oil sits on the surface of the part. When parked the oil is absorbed in to the parking a layer that will be as much as .005 thicker.
I find no real difference in the durability of hand guns VS holster ware in either finish. I would say the same would be true for a blade as well. I do find that blue sands and blast off easier than park because blue is thinner.
The only time I find bluing better is when I want a prettier, traditional or factory type finish or when I want a smoother finish with some degree of rust protection.
My 2 cents.
