Very throough and very long. First you send a cv and letter and then you do about seven hours of tests. Then the next stage is five more hours of tests. Then an interview. After, that there is two other interviews to get through. I didn't make it past the first interview, but nevertheless was a very long process to get there. Test questions are very broad and require numerical skills (no matter what role you're applying for) and lateral reasoning skills. The interview was standard HR stuff. I would say it was a long process - maybe too long - but also quite interesting and fair. It's clearly an interesting company.