The recruiters for the most part are really friends. Had two rounds over the phone and these cases focused on the division I was pursuing. Mostly pricing or strategy improvement. The super day was in office at Cambridge with 3 case interviews (at least 1 partner and then most people had at least senior consultant ranking for the other two). You also have a math exam and lunch interview.The senior consultant as mentioned here previously makes you do a simple excel exercise. The math exam is essentially GRE word problems in which if xyz happens, what happens to the variable. It is hard if you do not know what type of questions to expect. In office, 2 of the interviewers were cold and didn't seem too enthusiastic to be helping with recruiting.

I applied online through my school and got the email invitation for a phone interview + online numerical and logical reasoning test about 3 months later. First round interview was a 45 minutes phone interview with a senior consultant during which she went through my resume and work experience and a short market sizing question at the end. The next day, I received an email from the recruiter informing me I had passed the first interview and is invited to the Recruiting Day. I attended the Recruiting Day 3 weeks later, which began with a presentation on Simon Kucher & Partners by the Managing Partner, followed by 3 x 45 minutes interviews with a director, manager and senior consultant. The 3 interviews consisted of a short case study, a long case study (with 5 pages materials which we had 45 minutes to prepare our presentation) and a presentation on 3 slides which I had a week to prepare before the Recruiting Day. There were also questions on my resume and work experience for all 3 interviews. There was also a 20 minutes interview with the Managing Partner which was just going through my resume and answering any questions I had but really, it was to see whether you are a good fit for the company. There was also a short online numerical and logical reasoning test which was about the same difficulty as the one done previously, probably to make sure the candidates did the previous tests on their own. The entire Recruiting Day was very well organised and they even booked a restaurant for all the candidates and interviewers to have lunch together. There were no interviews or tests during the lunch but I presume it is to see how well you are able to fit in their culture.