I have three bikes set up with trekking bars, one has north roads, one has risers (my mtb, one has moustaches bars, and the other 7 have drop bars.

Like some others, I cannot sit upright on a bike and ride for any distance so the old 3 speed with the north road bars does not see a lot of mileage but the three speed with drop bars does, the mtb has a very aggressive / forward set up and is quite comfortable, and trekking bars are about as versatile as they come... but most of the time I am riding a bike with drop bars.

Besides the good hand positioning I can be more aero with drop bars and more aero is more efficient... as I can only pedal fully with one leg every little bit helps.

Could never abide flat bars... they have to be the worst type of bar to use.