Pros
Great work-life balance, stability and security of working for the only employer legally authorized to print money (i.e., the federal government), flexibility to set your own schedule, zero expectation to work overtime or work weekends, amazing amount of time off, accrual of sick time and vacation time is very generous, pay is good, and benefits (medical coverage, retirement plan, etc.) are very good.
Cons
Most everything you do from when you arrive for work to when you leave is less than pleasant. The work environment can be extremely frustrating. Massive amounts of ridiculous bureaucratic processes to get anything done. You have to somewhat disconnect from the job if you want to maintain your sanity working for a massive federal government agency.