Pros
Stable work environment Interesting and challenging projects Opportunities to travel Access to many smart people you can learn from Great place to train early in your career and if you don't let yourself get railroaded by utilization crazed mangers you can make an excellent career here.
Cons
Atmosphere varies tremendously from office to office Extremely corporate management structure. Because of the company structure there is a gigantic middle management. They are well paid and protective of their status. You only penetrate that group by toeing the corporate line, waving the company flag and making the manager above you look good. Technical skills mean very little as far as advancement. There is a level above this though where the very smart people reside in senior management. If you don't firmly but gently manage your career you will likely find yourself under utilized as far as skills and overworked as far as weekly hours. You can easily become burned out and angry. You can easily find yourself on the street if you break any corporate rules. It is not unusual to find an empty desk on Monday morning and find out someone got turfed for violating one of the many, many, many safety or conduct rules. Little explanation will be forthcoming about what really happened. This is to be expected in a large company where lawyers are writing the guidelines with an eye towards law suites