I'm a current Air Force GMO flight doc. It's been an incredible experience. I think it's great to see the operational side of the Air Force. Also, the opportunity to work with and care for such an amazing group of people doesn't exist in any other form that I know of. I actually get to see them train and perform the mission in order to understand the environment they work in and what it medically takes to do their jobs. I think it's made me a better doctor and problem-solver. Being a good GMO doc means you are motivated to help your patients. No one holds your hand, so it's up to you to find the information or call for help. Good docs will do that, bad docs will throw some motrin at the problem and go on about their day.
That said, I'm finished serving my HPSP commitment next summer and am right in the middle of applying for civilian residency, which is pretty nerve-wracking. I've definitely lost of a lot of medical knowledge and I know I'll be behind my peers when I start again. I guess another downside is having to go through the whole ERAS process twice - it's expensive, anxiety-provoking and time-consuming. I also wonder how programs are going to view me, since I've been out for 4 years. A big reason I decided not to continue with an active duty residency is the lack of flexibility in military medicine. You will see X number of patients and you will work whatever hours they want you to. They tell you exactly how you will practice and you don't get much of a say in it. While there is a reason for this, my future autonomy is important to me. Also, don't become a flight doc if you get motion sickness. Flying can be awesome, but some wind up hating it because they puke the whole time. Finally, some residency trained docs will be really nice and helpful but some will be straight up rude if you call them for advice and don't know something they thought you should as a GMO. You're a primary care doc trying to do the best you can with minimal training, so you'll have to swallow your pride and do that a lot for the good of your patients.
I hope this helps. I am definitely glad I did it. It's been an amazing adventure.