Well , I regularly fly with 4 ex mil FOs in my base and they all failed the upgrade on the first attempt and they were arrogant , over confident, had poor interpersonal skills , 2 of them had poor hygiene , and they all had issues with authority. I would love to have had a chance to operate a fast jet or any high performance military
aircraft and I think the experience you can get is excellent but as I said form what I have seen , more often than not they're just annoying to fly with Lack of humility and an inability to hold their hands up when they make a mistake is also an issue. Just an observation !