I ask because I was considering doing it. For those who are unfamiliar with it, I believe it is a one year hiatus to do research for the NIH in many (basic science/clinical) fields. It's a healthy stipend depending on cost-of-living and they have many locations from which one could work. They fund moving expenses and provide health insurance as well. Would seem like a golden ticket for residency. Though I wonder if it is worth bringing med school momentum to a halt for this experience. It means graduating a year later of course and is probably more designed for those with a greater interest in research than what I have.