Pros
Gorgeous offices in downtown DC, close to metro. The work day is only 7.5 hours, with an hour lunch, though some supervisors allow you to take just 30, making it 8 hours and then out. Free access to a gym. Free coffee. The people are generally pretty nice at the office. You are allowed to telework one day a week after 6 months. Some flexibility in hours, depending on your boss and position.
Cons
The pay is a bit low. Unfortunately, everything depends on where you work and who you work for. The telecommuting policy is uniform, but flexibility is not. Some departments let you work flex schedules while others are rigid and inflexible. There are a lot of rules in the handbook that are not applied uniformly. Some supervisors allow real flexibility with leave and doctors appointments, while others do not. It would be more helpful with uniformity, and better pay.