Pros
Incredible insight into EU policy-making and legislative procedures; proposals for EU legislation with huge influence (and responsibility); easy, laid-back working environment (in most departments, the typical 9 to 5 job, but there are exceptions), very good salary (income tax free) and benefits, ideal for not-too-ambitious professionals, excellent for work-life balance
Cons
Depending on the Directorate General, an overall disaffected work-force resting on long-overdue benefits and often out of touch with the industry they regulate; absurd recruiting procedures that utterly disregard experience in favour clueless young recruits (who are better able to ace the initial multiple-choice questionnaires); lack of direction due to the growing "politicisation" of management, career advancement extremely slow (and open only for the permanent staff) - only a post as a contractual or temporary agent recommended (max. 5 years)