Pros
The investment to keep you HAPPY is real and as a result, employees are, well, HAPPY! (gasp) Birthday and un-birthday coffees (half-bday month) are one way they do that, which allows you time to sit down and discuss your thoughts about your job with a member of the employee happiness team (yes, there's one of those). This is the kind of thing some new-age thing startups might do, but unheard of in government contracting. One of my favorite 'perks' is tickets to Washington DC area events and sports games. Though you may get hired for one role, there is latitude in the company with other contracts if you end up performing well at what you were hired for if you express interest and have the skills to back it up.
Cons
Sometimes this may come off as "trying to hard," but if you get past that, the benefits of it all are tangible.