Well, now that we've got the negative examples of military pilots transitioning to 121, here are some positives that I always appreciate when flying with them.

Military pilots usually know the plane backwards and forwards. The systems knowledge is useful to diagnose problems and to make better decisions. They also are good with charts/graphs/etc so depending on the jet you fly at a 121, that's also extremely helpful. I also appreciate that military pilots generally understand the importance of doing things the right way and not taking shortcuts. They're predicable and reliable once they settle into 121.

That's been my experience anyway, so another 2¢ to the pile. Every group has bad apples, but I always look forward to flying with military pilots.