Pros
Benefits. The medical is really good. You get access to online training and books 24/7.com. If you're looking to move around or get a job which pays per diem, this is an excellent opportunity. Great opportunity for entry level without roots or for empty nesters who can work in another city during the week then come home on the weekends. If you're willing to move or travel, this is really the company for you.
Cons
Unless you live near a big city or military base it's tough to find a different position within the company. You generally don't have the option to "get benched" either you're on a contract or you're out... there's no 2 weeks to find something else either; you're working until the end. While it may say that travel is 25%, expect more. The paperwork is overwhelming if you're farmed out on a contract vs. an office employee. Doesn't automatically provide you with a computer or internet access; you may be using your own phone/computer/internet/supplies even if your contract says it's furnished. Check that your taxes are being paid to your state or you'll end up with a huge bill at the end of the year.