Pros
General Motors is a large manufacturing company and employs thousands of people. Thus, there is lots of opportunity to grow and learn the different facets of manufacturing if that is what you want to do. They have awesome buildings and loyal people who have helped this company function for 100 years. They pay a good salary and have one of the best total overall compensation packages anywhere. They have lots of experienced people who are proud of what they do and where they work and you can almost always find someone to relate to and there is a good sense of camraderie at the company.
Cons
Because general motors is so big and old, that is part of its success but also part of its failure. It has to manage a large number of people and models all over the world and it seems like it is doing a bad job of this. Because it has been around a long time, its employees are proud of what they do and where they work. This is good but is also bad because new ideas from fresh employees are discouraged and thus the fresh employees lose their creativity and the fresh ideas are non existent and thus the company continues to build the same products over and over and do not adapt to the changing consumer.