Pros
Training - Depending which departments you work, your manager may or may not give you any chances for training. I had worked for 2 different groups and was always given opportunity to try out various training programs. The training classes were either in another city, in the same city or you will do the training class from home.
Cons
Communication - Being a very large organization, getting the information to pass to various IT departments caused a lot of headaches between various IT groups. If these various groups could learn to communicate and understand each other better, some things can be run more smoothly and less obstacles since as an organization we all have the same goals to make this company very profitable and make sure all of the employees are happy and content to work at this place.