You will probably get 50/50 answers on this question. Some folks cant stand a shiny gun and others love them. I like a stainless slide on some guns and blue on others. Its just a matter of preference. Some people think a stainless gun may reflect light at night and cause them a problem. I probably wouldnt ever choose hard crome, but thats just me.
I like contrast. Id go brushed nickel or hard chrome. Keep in mine nickel is corrosion resistant, and herd chrome is wear resistant. If the hard chromed one is done by a reputable manufacterer or a good smith then it should be nickeled under the chrome which will give you the best of both finishes.