Three step interview process. Interview, dinner, then two additional interviews with senior management. First interview was with two senior consultants who will drill you on every detail on your resume. Next they invite you over for an evening dinner if you quality, after that you are interviewed by a senior manager and then separately with a partner at the firm. They ask questions in a way to see if you'll emotionally react to odd and overly challenging situations. (Hint: keep your cool, its all a test).

I went through two interviews. The first interview included the behavioral part and case part. The second interview was with a managing director, and the entire interview was about solving a M&A case.