I had an interview on campus that consisted of mostly "Describe a situation when..." for me I found this relatively easy, some people I talked to found them difficult though. I then was asked to go to Virginia for their final round of interviews, they seemed to ask roughly half of those they interviewed to the final round. There I had three separate interviews Case, Behavioral, and Technical. The Case was reasonably simple, but I actually ended up screwing up a bit at the end. The technical questions and behavioral were pretty easy. The technical question was essentially, write a program where you are given a string and find the substring. Over all it was a pretty nice interview process and they make sure you're completely comfortable. They even let you talk to employees at a restaurant before the interviews so you are more relaxed.