The interview was very low key, there were about 6 people in the first round of interviews (starting at 10am) and about 5 for the later interviews. Pesronally I liked having the interviews first thing in the day so I could enjoy the tour and the lunch more, I dont think I would have eaten anything if I still had to interview.
The open file interview was more of a conversation than an interview. He would comment on something on my file and then ask about it, but it was very low key and low stress. The closed file interview was more stressful for me.