I did a mock interview with Sanford ahead of my R1 HBS Interview and was admitted to the HBS class of 2017. I must say that this mock was crucial in my interview preparation. Sandy was very well prepared and familiar with my app, and the tailored questions he asked were similar to the actual interview (no generic bs). His feedback was very straightforward and to the point as well. I would recommend a mock interview with Sanford for anyone with an HBS / any business school interview.