Pros
you will see all aspects of the business should you elect to get involved or not. Early on you will see how depts interact to get the business of making steel done. Once participating in the chaotic environment, it will seem overwhelming and you will either sink or swim to keep up with what you perceive to be the way the business world must operate. So you will knuckle down and show that you can swim with the best of them, learning along the way about the industry. This is where the good stops.
Cons
then one day you will wake up and wonder where the last X years have gone. Certainly not unique to ArcelorMittal, but this is your reward nonetheless. You'll begin to wonder why you now spend more time in MS Office and as every day drudges along, less time in the field doing what you love. This is not the company for the person who wants decisionmaking at the ground level.