After being referred by current employee, I had an hour and a half phone interview with a partner. This was conversational and behavioral. The partner sought to determine competency, personality, and why you wanted to work for the firm.
The final round interview was an office visit with 2 one on one interviews that lasted about an hour each. These were also behavioral and conversational. Throughout both the phone and in person interviews, questions were encouraged, so be prepared with 10 or more questions that can focus on research you did on the firm, personal questions for your interviewer, or corporate culture and day to day functions.
Overall, the firm has a great corporate culture. Teamwork is emphasized, and there doesn't seem to be the internal cut throat competitive nature found at other consulting firms.
