I applied for the Business Analyst position in October 2015 for the Los Angeles office. It was a very straightforward interview process. I went to their table at my university career fair, and they were very nice. The next day, I met with them in our career center for a 30-minute interview (more of an overview of my resume, why I wanted to do consulting, basics of the application process). About a month later, I had my second round interview. It was with a current consultant. The first 15 minutes were some questions he had for me. The next 30 minutes were dedicated for me to lead the interview and "pick" his brain for any and all information I wanted to know. The topics were up to me, but I asked about the life of a consultant, the day-to-day tasks and career planning in the company, etc. This was very valuable, so come with questions beforehand.
About a month later, I was invited to the final round in-house interview, which consisted of one interview with a manager and a group case presentation. After their initial presentation, I had a single interview with one of the managers who was in charge of the group I applied for (BA for me, SD or SE for other people). The interview was relaxed and was more an opportunity for me to speak with someone who had been with the company for a while and see if this was a good fit for me. The main part of the in-house interview came with our group case. We were given the prompt the day before, but we got the "ask" the day of. It wasn't a technical case, as it focused more around the requirements gathering from the "CEO" and then presenting our conclusion in an effective way.