Unlike some reviews, I did not get to the face to face interview. I applied through an employee referral as well as their online website. I got rejected by their ATS but I was able to to use the employee referral to the next steps. The process took 4 weeks.
I got interviewed by HR, a Director, and a VP. These interviews were phone interviews that lasted an hour. I was impressed by how professional HR and my conversations were with the VP and Director. The phone interviews were to establish cultural fit and what I can provide to AP with my background. The format was very conversational and not adversarial as I expected. I thought I had a good rapport with the VP and Director.
Things moved quickly and I was waiting for feedback from the MD who made the hiring decision to move on. Unfortunately, he was on vacation and I had to wait an extra week until he returned. Once he returned, I waited a couple of days for him to review feedback and I was notified that he would not want me to move forward to the next steps.
I believe the success in getting to the next steps with AP was to work with its competitors (McKinsey, Bain, etc...). Most of the bios on the AP website are people who worked at prior management consultant firms. I believe that one who has not worked at prior management consulting firms would have a very slim chance in the AP interview process. AP is extremely picky in its hiring process in spite of the numerous open positions.