Pros
The benefits package is pretty awesome. Though experiences vary significantly from one department to the next, generally speaking: There is a great deal of opportunity to transition between teams and get promoted. Several departments offer flextime and/or work-from-home opportunities. There is a focus on employee development. High-performing employees are visibly recognized. Expectations are clearly communicated. Some departments have a strong focus on work-life balance.
Cons
Some departments have a poor or very poor work-life balance. Promotion is usually more dependent on who you know, not how you do; this has become institutionalized--lackluster networking is interpreted as a lack of managerial aptitude. Political mis-steps can result in disciplinary action including termination. It is very hard to improve your personal brand if it becomes tainted; upper management routinely discuss employees and a negative reputation will spread.