I started off with flatbar bikes but did convert to drops, mainly because in the exposed flat countryside near me, cycling upright into the wind for miles was no fun. Now, I wouldn't use anything else for long trips and my only flatbar is a turbo trainer.
I would take issue with the 'multiple positions' advantage argument for drops, though. I could happily cycle just as far with a flatbar (fitted with ergon grips) and feel no need whatsoever to change the position of my hands. With drops, though, it's a very different story, and I switch from bar to hoods to drop fairly regularly because no single position is really comfortable for a prolonged time.
The top bar position on drops is not really comparable - for a start, for me, flatbars are at their most comfortable with a stem 30mm longer than one for drops, plus your arms are further apart. Ergon grips stop your wrists bending to extreme and make a real difference to comfort.
John