Vantaggi
There are a lot a resources for research support--money to support co-authors, money for conference travel, money to organize small conferences, and money to buy data. This is one of the world's largest concentration of PhDs with an interest in agricultural economics. There are opportunities to do policy-relevant research, and ERS has a reputation among agricultural policymakers and stakeholders for doing good empirical research. The work-life balance is good. It's possible (although becoming more difficult) to be promoted to the GS-15 level as a researcher without having to go into management.
Svantaggi
The standards for what is good research are those of agricultural economics, which tend to be different from (some would say lower than) the standards in the rest of economics. In one sense this is good, because the bar for promotion should be lower. But some of the senior management (as opposed to branch chiefs) don't seem to be able to tell the difference between high quality research and low quality research, or at least they don't seem to reward it. There is a review process for promotion, but it's fairly opaque. Compensation is good for agricultural economics, but on the low side for economics. Some of the more experienced staff (of which there are many) are about 20 years behind the research frontier. Some of these same experienced staff have no respect for newer staff if the newer staff did not grow up on a farm, even though in many cases the newer staff have better econometric skills. In some cases the lack of respect is quite overt. Management seems to recognize this, but they don't seem to be able to do anything about it.