I ride with my hands in the center for two reasons. The first being that I don't have grips on my handlebars, so I don't have a "set" location for my hands to be. Secondly, my stem drops my bullhorns pretty low, so it can get uncomfortable leaning over when my hands are spaced farther (not to say that I always ride with my hands in the center, otherwise I would have bars like the chopped ones above).