I'm partial to brown. I don't know, but it just looks good. Blued barrels are nice, but the brown tends to hold up better in my opinion.

I prefer browning and use laurel mountain forge. Found I like to quit applying after the 3rd application. After that I just lightly rub down with a rough wet shop rag (the red ones), let it sit over night and do that until I get the color I want (it's a slower process). It keeps rusting until you neutralize with a baking soda slurry and then oil it down good. This method, for me, gives a slightly smoother more even finish. If you want a little rougher finish you keep applying the browning agent until you get the color you want