D did local interviews with alumni for Harvard, Princeton, Yale, Carnegie Mellon and one local interview with an Adcom for U of Rochester. Had wonderful experiences with all of them except the Yale interviewer. He had her come to the law firm where he was a senior partner and kept her waiting and waiting. She said they never really connected. She couldn't get a chuckle out of him. Turns out he was the uncle of a classmate. He told the classmate that the interviews do not make or break a candidate. She did not get into Harvard, Yale or Princeton. Accepted to CMU and U of R. Attending Stanford, where they only are just piloting alumni interviews and she did not interview.
I hope this helps. Good luck.