Pros
Large company and could learn about how to manage politics. It is cool to work on things that are about four years out and get to see from start to finish. General Motors is quite a powerful company name to use while working with suppliers or other engineering forums. Most people think you have to be quite talented to be accepted at one of the big automotive companies vs. a supplier.
Cons
Politics could get in the way of advancement. The company is so large that you can become a number quite quickly if you don't know how to work the system or get involved in internal organizations to become aquatinted with leadership. The leadership is on the conservative side and runs more on a old school business style. Example: If your a female, do not be too trendy/tailored in your suits, wear more than a base in make-up and wear your hair styled. The organization is big on you knowing what level you are within the company and not working with people above your level unless approved. Very layered company.