Well, it depends on where you want to be. As a general rule, and to the chagrin of many medical students applying in recent years, Radiology has become a very competitive specialty. Most successful candidates going to top programs have solid pre-clinical grades, stellar step I scores (>220), and excellent clinical rotations and letters. Many of top programs have their share of AOA's as well. Radiology represents much of the way medicine is evolving, high technology, minimally invasive, quick, and accurate. Not to mention, a great lifestyle, excellent earning potential, and job availability. If you want to compare the selectivity of Radiology with other specialties, I would put it up there with Optho and Derm. I hope this was helpful.