Pros
Salary is higher than average, and employees are very professional. You can learn a lot here. Lots of opportunity, especially if you are willing to relocate. Even though it's a HUGE company, I find its very much like running my own business. You have enough rope to run - to succeed if you're a self-starter, and enough to hang yourself if you're not. This is a good place for a talented, energetic individual. If you just want to put in your 40 hours and go home look elsewhere.
Cons
If you're not billing to a project you are in danger of being laid off, and good performance may not be enough to save you. As a publicly traded company, the bottom line is more important than anything. Constantly repeated slogans such as "People are our greatest resource" spawn a lot of jokes.