On an over the counter gun, I like stainless to start with, from there treat it for it's intended use. Hard chrome is my finish of choice for lubricity and wear characteristics, that you can have done in the states. The tenifer finish on Glocks is the toughest finish I've ever seen, the dark finish is not tenifer, it's phosphate over tenifer, tenifer is extremely corrosion resistant, and penetrates .003'' into the metal with a rockwell hardness if I remember right of 63. A good file won't hardly scratch it. I do Dura Coat finishes and like them as well, on a working gun, it don't have to be pretty, just blend in the way you want it to. The Dura coat parkerized look black finish is really good, no shine and coats evenly. You spray the wear areas 2-3 times more than the none wear areas. The muzzle, edges of the slide where the holster will rub. It will wear off in time in these areas. I love parkerizing, the rough texture of the phosphate is tough and gives lubricant and preservative a place to hang out, not easy to wipe off. Non glare, the military got that one right. My barbeque gun has got to be a high polish, royal blue, or high polish stainless, I just never have cared for nickel. Fine guns should have fine finishes, but I don't buy too many of those.
My 2 cents and change.