It's all a matter of perspective. You need to define that before deciding on the best path.
I love paintball, it's a taste of life and death on a battlefield. Outdoor is better but indoor is good too. If any of it were real, I would have been dead many times.
I'm guessing with modern technology, you might not ever have to worry about running around a forest getting shot at by enemies that are difficult to see. I'm sure it's still important for a Marine to be experienced with that kind of combat.
Isreal has the Palestinian children all worked up. They have a policy where they are not suppose to kill children, but the parents are fair game. Sometimes they do kill the kids though. They are raised to hate Isreal. The same thing is happening in Iraq and Afghanistan, where the US troops are having rocks thrown at them.
Them boys look like their having a blast.
EDIT: That image at 1:00. Inspires more than that Chinese guy standing infront of the tank.