I moved from a flat bar MTB to a roadie with drops. Personally I prefer the drops, they let me get into different postures while I'm riding. Also, has anyone ever tried riding no-handed and using their arms as a pendulum (like when you walk or run)? For some reason, doing that always helped me with pedalling and felt a lot more natural. Drop bars let me do pretty much that except without taking my hands off the bars.
Oh and yeah, I can pretend to have flat bars if I'm feeling like a more casual ride, and want to sit upright. Only difference is that that loses me the brakes, but it's not a big deal to move my hands over onto the sides, still being upright, when I might need the brakes.