Originally Posted by MalteseX

I'm not sure what you are asking---so I will go through your post and questions point-by-point.

You say you want to fly for an "airline or a business like UPS."

What are the pros and cons of having 4 years military experience.
Pros---many; military service is looked upon very favorably unless you are working for some anti-military organization or a state college.
Cons--you can get killed; you can become disabled

What are the pros and cons of having 10 years of piloting experience in the military?
Pros--military guys get hired at all airlines in very big numbers/percentage. You get paid very very well in training and with an adequate salary. You won't incur seemingly insurmountable expenses while getting your ratings and/or getting low pay in your early years by going the flight instruction/regional route.
Cons--10 year commitment. You will be older/behind in seniority numbers. You have to "put up" with all the military BS (deployments, etc.) I know at age 18 this is fun, but it won't be at age 30 with a family.

By the way there is no advanced placement by being a military guy. Your seniority starts at the bottom for most airline/flying jobs.

Best route: Go reserves or guard and serve your commitment there. You can then start looking for civilian flying jobs as soon as you are qualified vs having to wait until the long commitment is completed.