Not that I'd recommend my method of advancement but I've accomplished both training routes so I feel qualified to comment.

I was a CFI and Director of Flight Training before I entered the military. I've flown corporate (right seat only), night freight (727's), charters, civilian CFI, flown caskets (corpse included), dropped jumpers from C-206's, and many other things to build time. I've spent 13 years flying military fighter aircraft and a tour in T-38's. I was an instructor in both the F-15 and T-38 before ending up at my major airline.

I agree that it entirely depends upon the individual pilot. The one thing you can say about ex-military is that at at least one point in their careers they met a certain standard that "some" civilian trained pilots could not meet. That does not mean they could still pass that same standard today. Some civilian only pilots would not have made it through military flight school. However, many if not most civilian trained pilots could make it through military flight training because all capable people don't necessarily enter the military. There are many highly capable pilots who choose the civilian route for valid reasons.

On the other hand, the military does act as a screening mechanism for many pilots who shouldn't make the grade. In the civilian world there is no such screening mechanism, although it is better today than it has been in the past. Today a hiring company can request the training records of past employers when looking at pilot applicants. In the past this was not the practice and one slug of a pilot could plod from company to company until he gained the time required for a choice job. The best do not always rise to the top.

From my personal experience I prefer flying with ex-military pilots. At times they can have ego problems but many times confidence in their ability is confused for a large ego. I have found that at times they need to focus a bit more on passenger comfort/service and less on "the mission" of flying from point A to point B. They are more of a known quantity and while I may not agree with their politics or like their personality, their flying skills have not been questionable so far. When trying to pick out the top pilots I've flown with over my career, all except one man were ex-military. I'm sure there are exceptions.

As far a civilian trained pilots, many/most are outstanding. I can say however that the very few pilots I've flown with in the airline business that I feel do not belong in a cockpit are all from a civilian background. I won't get into specifics about each individual and I'm not sure if their training had anything to do with their skills but that's just my experience.