Pros
Great pay and benefits, especially after a few years. Pretty much everyone gets a raise every year (of various amounts), so after several years, you'll be making well above industry average. Flat corporate structure without too much office politics, although that is changing as the company gets bigger. Paid trip once a year at a vacation spot for you and your family. Fast is really good at what they do. They treat the clients really well, although sometimes at the expense of their employees. Working for Fast means that you will be working on successful projects.
Cons
You have almost no control of your career at Fast. Negotiating salary or position is forbidden. You have very little say in where you will be living or what you will be working on. Over the years, I've seen many people dropped in bad situations without being able to do much about it. Your experience at Fast will vary greatly depending on where you are working and what you are working on. Unfortunately, you have very little say in those things.