They were nice and sweet the entire time. I had an on campus interview and then I was invited to Superday.
Both of my on campus interviewers during the first round were really down to Earth and professional at the same time. The interview went more like a conversation than it did a line of questioning.
Superday was a little different. It's five 30 minute interviews in a row, and not everyone was as casual as my initial interviewers. You have to be ready for different personality types, and don't feel bad about repeating yourself throughout the interviews.