Simple answer and cynical answer is that competitiveness is correlated to practicing physician's salary. Look online.
Unfortunately once you finish internship, residency, and fellowship, things usually change dramatically particularly in fields such as radiology, derm, ophtho...Things like Nsurg, ENT, uro...they are relatively stable. Do what you like because you are going to be working 'free' for many many years...
Remember that the more competitive a program is, the more opportunity they can have to take advantage and abuse you as a resident. Imagine your program director telling you, if you aren't happy then we can find someone else to work for free...That is probably quite common in radiology.