Drop toe or drop heel?

I used to pedal with my toes pointed down. A friend suggested I lower my saddle so that at the bottom of the stroke my foot was flat or even my heel was dropped. I did so, maybe 1/2" lower. By now I've pedaled this way for a month, including a number of 50 milers and a recent 12 hour day.

I don't notice much, or any really, difference.

How do you pedal? What are the pros and cons?