Two-step interview: first with a principal and second with two principals/managers. The interview was largely behavioral though showing that you have subject matter expertise is really important. They also value your personality and your ability to fit into the firm culture.

The process included an initial phone screen, a panel interview with two director level professionals and then an HR interview talking about my skills and assessing company fit. Took about 3 to 4 weeks, but the process was fairly straightforward and everyone was really nice.