Be prepared to answer the same questions several times with different interviewers. Most of the questions are designed to let the candidate describe a situation where he/she used certain skills the interviewers think are relevant. Overall everyone was kind. Be prepared to brag - the format of the interview is setup to facilitate this process and if you are not prepared it can be overwhelming. Would also recommend having several of your own questions. They are welcomed by the interviewers and do a great job of temporarily deflecting attention during the 3+ hours which can be a nice break.