The company tries to be very thorough in hiring processes in order to hire the right people, but, unfortunately, I think they over complicated it and didn't communicate it effectively to the staff involved, missed some essential user experience considerations. I got to the second-last stage and I left each stage feeling very frustrated at the company and with the impression that I wouldn't enjoy working there.
This is the only company where I've experienced a 6 stage interview process (for a mid level position) , as well as prep calls with HR before each stage and follow up calls after each, thus feeling like 18 stages. On top of this the calls and interviews were only ever confirmed over email, no calendar invite, which seemed clunky and was difficult to manage. Also, communication internally between stages seemed poor. The second round call time was changed, then the interviewer was changed 30 mins beforehand and it was obvious he didn't prepare as he was trying to ask me long term case study strategy questions with only 10 minutes remaining as if he was trying to complete the entire hiring process in 1 hour.
Stages: 1. screening call with HR, 2. Short marketing hard skills interview with team lead, 3. Practical test, 4. Cultural fit interview with a peer/teammate, 5. Hard skills interview and presentation of practical test with hiring manager and one other, 6. Executive interview with head of department or C level.