Pros
It's easy to impress people, because most of your peers will never go above and beyond. There WAS a pension plan that made their compensation package competitive, but that went away a couple of years ago. Your salary can START seemingly high.
Cons
Company has promotion guidelines, but does not follow them and your performance doesn't matter. You can be a stellar performer at pay grade x and the worst performer at pay grade x+2 will get the same percent increase you do, which equates to a lot more actual dollars for the lackluster performance. People never get demoted, so there is never freed up budget to reward the performers. Meanwhile, you can never get promoted unless you are at the top of your manager's list AND there is a budget for promotions AND you've been around 3 times longer than the promotion schedule AND you have dirt on someone. Additionally, you will not attain any new skills that translate to other industries. It's a bad career move to come to Y-12, unless you plan on staying until retirement.