I had a 1:1 on campus interview with the company after they asked me to apply to the position. The first interview was not difficult and consisted of some behavioral questions and a mini case interview. After initial 1:1, I was invited up to their office in North Carolina for a full day of interviews. Before the full day of interviews, a couple of employees took a group of us out to dinner.
The full day of interviews consisted of 4 1:1 interviews (some of which were case interviews with a lot of emphasis on being able to do mental math very quickly) and a case interview. For the case interview, each interviewee worked individually and then we worked as a group. After we had finalized the case, we presented the case to the head of marketing, who grilled us and played devil's advocate. It was personally too intense for my style.
They do have nice facilities in NC and the people that worked there seemed to enjoy it. They seem to have a really fast-paced and intense work environment. Overall, it seemed like a good place to work if you fit the culture at the company (which I did not).