Had a somewhat difficult time answering this without skewing the results. I have aero bars on my bike which I use for the 1/4 to 1/3 of my commute that's on a bikeway. Any time I spend on the aero bars is time I'd likely be in the drops if they weren't there.

I spend a lot of time in the drops and adjust my bars so that I'm comfortable in that position. To me that is where the braking is optimal but I suppose that depends on your hands and where you've got the levers positioned.

IMHO if you're riding on the tops most of the time you've got the wrong bars or they are adjusted wrong. You can't shift from there and on most bikes you can't brake. I wouldn't say the same in regards to hoods.