Pros
Th experience is second to none. In just under two years I have built a resume that is very impressive. In addition, as I have started looking for a new position elsewhere, I actually get calls back from very large and respected companies. Do it for the experience if for nothing else. And if you love to travel, then this is also the best way to go.
Cons
If you have a family, like I do, the travel is a bit much. Travel is 100% for the most part, but in my experience, if you prove your value then there is room to maneuver in terms of flexibility in terms of a travel schedule that works for you. However, if you are in Chicago and the client is in New Jersey well then you are out of luck. Just no way around it if you want to stay on the project.