I don't care for risers/flat bars, they get tiring after a while and I try to do longer (20+) mile rides pretty regularly. I like bullhorns because I feel like they make acceleration from stops a bit easier, which when riding in the city is pretty frequently necessary.
My bike came with road drops, but I didn't ride them for long. I suppose I just didn't like that particular style of bars, but I may try some others in the future.