I think that although anyone can learn to fly, some have more natural aptitude than others.
Assuming that the military are looking for ability, responsibility etc., then there is a filter process going on in the military that simply doesn't exist for civvy flying - as long as the civvy has cash, he can keep flying as long as he passes the tests. If the civvy is CPL/ATPL, there will probably be a job for him/her somewhere.
The mil also offer a rounded package of training, so on balance they will have a broader training than civvys, many of whom never get to night or instrument unless they go full ATPL.
So in the absence of any other knowledge about an individual (blind choosing a pilot), I'd take the mil. man.
As soon as you start to know the individual's character, you can make a more informed choice, however I would say that out of 100 random mil. pilots and 100 random civvy pilots with the same hours and the same exposure to training, the filter process in the military is bound to have an impact on the standard of the mil. pilots.
On average.
Excludes individuals! your mileage may vary....
BW