Fairly complicated interview process; was brought in twice to meet with two different groups of interviewers, even though I had already worked there as a contractor for six months. Due to government bureaucracy, I waited at least two weeks to find out that I was the candidate they had chosen. They asked a lot of the old-school, essay-style interview questions, eg "Describe a moment on the job where you handled a difficult problem/ Made a mistake/ Dealt with a problematic boss or coworker." I would definitely prepare answers beforehand, because being judged by a panel is slightly nerve-wracking (at least, it was for me.) It is a formal, corporate environment, so wear a conservative suit to the interview. (On the job, it is business casual.)