Pros
Great place to start your career and a great place to grow depending on if you find the right project for you that fits your interest and work life balance desire. The opportunity to travel is there if you want it. There is a lot of support for new hires. The company manages change management communications adequately and you generally get the impression that you are cared about as an employee. This instills loyalty and I think twice about leaving and will definitely make me very scrutinous when searching for new opportunities.
Cons
As with all jobs, your quality of life depends a lot on your immediate management. Luckily if you are in a completely untenable situation you have resources to get out of it if you need to. If you aren't on a good project the benefits of working for a well organized company can be diminished as it tends to feel like you are working under the culture of your client organization.