Pros
Excellent benefits. Can't beat them. Peers, for the most part, are supportive and collaborative. If you work on contract (gov't contractor), you're golden, but keep in mind that being on a gov't contract means you are not advancing in career. Ever.
Cons
The company is experiencing growing pains, and while the work is challenging and fun at times, it is important to remember: some executives are to be avoided. There is a clearly defined line between which employees are staying, no matter how morally and ethically wrong they treat other individuals within the organization, and which ones are expendable. Be careful. Keep your mouth shut, do your work, and go home. Don't talk to anyone about anything personal unless you trust them. I've witnessed back-office employees treated beyond horrible.