A few years ago, I applied to both civilian and Navy dermatology residency programs (I ended up taking the Navy residency for personal reasons). Although I had good grades and board scores, in respect to my civilian application, I considered myself an average applicant in the ultra-competitive field of dermatology. However, I believe my flight surgeon experience helped me stand out in a positive way with my civilian applications. I was offered civilian interviews in the double-digits and was pleasantly surprised. I'm confident that I would have matched in a civilian dermatology residency (I never found out because with my Navy Derm acceptance in December, I closed down my civilian applications before "the match" in March).
I applied through ERAS. In the competitive residencies, such as Derm, it is rare to be offered an acceptance outside the match (although, it is possible). In less competitive residencies, I'm sure that getting an offer outside the match is more of a possibility
No programs required me to repeat my internship.
In my civilian personal statement and CV, I wrote about my military and flight surgeon experience, how it made me a better, more mature physician with real world experiences, and how it helped me confirm my interest in my field of choice. I think that helped tremendously because many civilian programs were interested in these unique experiences and expressed a "Thank You" for my service.
My advice is that not everybody in the civilian world will view your military experience as a positive. Some people do not like the military. During your interviews, be prepared to answer questions about your military experience. Be prepared for tough questions about your thoughts about the "War on Terrorism" and politics. I tried to avoid conflict by saying "although I do not always agree with our political leaders decisions, my job as a military physician is to support my troops and provide the best medical care in any environment, whether it be during peacetime or in difficult combat conditions".