Pluspunten
Great benefits (401k, profit sharing, decent vision / dental / health insurance (though premiums are getting out of control))
Once great company culture - more below
Training budget unlimited*
Will promote based on merit - also see below.
Minpunten
Salary not competitive with market, often far below average. Benefits are great but do not cover the gap.
Govt. Contractor - as such, you're inheriting a second-class citizenship: federal personnel act as if they're lords and ladies of the land while you're a filthy peasant. Management sympathizes, but ultimately kowtows - that's their meal ticket, afterall.
Culture is changing, and in a bad way. I used to feel that despite the above, the company really cared about and invested in their personnel. However, the prevailing attitude has shifted toward a more corporate mindset: overworking most talented employees, treating employees as expendable numbers, and tightening down on benefits that were once encouraged all smack of an increasingly corporate-level greed.
Company will happily promote you - just don't expect a significant raise. You'll still be making less than the people you're expected to manage.