Of my career spanning over 1.5 decade I would say that this is the only interview which was so well planned and executed. Entire process was managed so professionally which I had never experienced in the past.
Even though scheduling the first interview took some time because of the year end vacations , but after that all was good.
Hiring manager was there through out all the rounds as one of the panels , which is a very good as he gets a 360 degree of the candidate being interviewed. Unlike other interviews where in the interviewer wants to show how much does he know here it is the other way round where in they want to see what you know.
They would be taking notes on each and every word you speak which they use for their evaluation.
Key success factor what I think is the allocated time ( very particular) about the same, interviewers should be given the chance to ask all the questions that they have there in their evaluation sheet. Which means you need to be very crisp and accurate in answering the questions to the point. Make sure all your answers are backed by EXAMPLES. EXAMPLE yes I mean that. This is very critical success factor