Although this was my first interview, I doubt I will have any others as laid back as this one. The interview focused mostly on my application and experiences. It was rather conversational; although my interviewer asked most of the questions, they were not from a checklist but flowed based on the previous answer.
The facilities at Vanderbilt are great. The classrooms are right next to the hospital, VA, clinics, and the gorgeous, new Children's Hospital. Administration seems really supportive of students.
Many others have mentioned it, but be warned that the interview day is not very structured. If you don't want to be bored, take the iniative to walk around the facilities, drop in either the first or second year classes, talk to your fellow applicants in the lounge, etc.