Pros
GMAC used to be very entrepreneurial with a sense of family and common goal. We felt respect and valued. Not sure how it is now, but for me the biggest pro, was the people I worked with. My manager at the time was very people-oriented which provided incentive to work harder, take calculated risks, and hold myself to a higher standard.
Cons
BUREAUCRACY!! Upper management got in the way, constantly second guessed everything then felt the need to fix the resulting malaise and decline in morale with programs and initiatives that further eroded the time we had to perform our core functions. It was a downward spiral of confusion, angst, and the feeling that we were not valued by the organization. A significant amount of good talent left the organization during those times.