Plain edge makes the most sense for my general uses and sharpening equipment. I do more slicing, draw cuts, and detail work than I do sawing or cutting through dense / fibrous materials.
Serrations offer more edge retention and will cut better than a plain edge when relatively dull, but I'm no woodsman. There's rarely more than 24 hours in between my access to sharpening equipment - which is also why I have been much less of a steel snob than I used to be. AUS8, BD1, 154CM, 8CR... All perfectly fine for my general needs, and having them in plain edges makes bringing them to a hair-splitting sharpness takes only a few minutes with a strop.
I'd probably carry a serrated knife if I worked in a more industrial setting, like a warehouse or shipyard. I also have no delusions about my lack of knife combat training, so the intimidation and combat effectiveness of serrations are meaningless to me at present.
Moreover, I generally dislike the appearance of serrations on knives. Too aggressive and intimidating - I don't need to scare people when I'm opening a package.
I do like the look of serrations on the Vaquero, though. That and the Matriarch / Civilian are knives that seem strange without serrations.