I applied through a recruiter. The process took 3 months. I interviewed at Simon-Kucher (Cambridge, MA) in Aug 2018
Interview
Two phone screenings, then in almost THREE MONTHS I got an invitation for an on-site interview. Two interviewers, one from US one from Bonn HQ (VP level). The office is very nice, young crowd, the interview tone was friendly, casual.
Interview questions [1]
Question 1
Regular questions: about past achievements, problem solving, past history, experience in various mostly non technical areas. A couple of problem solving and situational questions.