Pros
Passionate co-workers who want to do a good job and make an impact. Good benefits and retirement structure. Leave - plenty of time off, easy to bank and use when needed. Insurance (medical specifically) 100% paid for employees and is very good. I hear others say 'it used to be better", but as someone who came from private industry, my opinion is it very good. Co-pays, etc are affordable. I do carry dependent coverage; and yes, compared to private industry, very affordable.
Cons
Pay is low..Can you afford to work for them???.. but benefits are very nice.