I basically agree with all of what previous posters have said, but thought I would share my experience on the other side of this type of program.
I'm about to be married to someone who graduated from medical school in May, so basically we had to choose a residency for my honey BEFORE I could begin applying to medical schools. Clearly, if I did not get into the school in that city, life would get very ugly for us in a hurry.
Under these circumstances, applying EDP made all the difference in the world for me. The school saw that I was committed to coming there, and since I'm living out of state I think that really helped me gain admission. On the upside, too, these difficult circumstances resulted in saving thousands of dollars on app fees and travel. Plus, I was done with the admissions process by the end of September and could concentrate on my current graduate studies, secure in the knowledge that I would be attending my first-choice school in a year.
I would say choose this path with caution, since there is clearly a large risk involved, but it is not a bad idea in all circumstances.