Pros
The organization offers stable employment and great benefits. After surviving 10+ years in public accounting, the pace and sense of urgency was, and continues to be, a culture shock. Compensation overall (including benefits, number of hours worked amongst other factors) exceeds what the private sector is currently able to offer given the state of the labor market. You will have plenty of time to address whatever you have outside of the office.
Kontras
There is little incentive to try to excel. Lower level management (they call it front line) can treat employees with the impunity. In NYC, the union plays a major role in the dynamics of the workplace, keeping management in check. There are too many folks who have been there 20+ years that have little or weak background in tax law. More so than usual, promotions come to those who are liked, and are yes men but are not necessarily competent. Administrative burden can be overwhelming to the point that you wonder if you function is to challenge taxpayers or complete paper work. After you stay too long, It can be difficult to leave, although this might not necessarily be a bad thing depending on your situation.