The interview process was a bit sloppy and confusing. They sent me a test, didn't like it, I did it again. Eventually they invited me in.
Initially 4 hours interview, with people from many teams. Questions about algorithm, systems design, team fit, code review of my test. Overall pretty simple to me. The algorithm part was much easier than other big companies. System design was vague and as I was discussing my solution I had the impression the interviewer knew much less than me. They made me do the test in Java, but all were Scala devs. At the code review they were confused by Java, so I had to explain a lot. All in all I can see the interview is little about skills and a lot about being good at selling yourself and talking.
Then the weird part comes. The company has several teams, and initially I really wanted to know what position I was actually running for. They insisted all positions were open and if I was passing the interview I could have chosen. But then I noticed they were pushing hard for a certain project. I was not interested in it, both because the team felt made by very pedantic people and because I found it uninteresting. Nevertheless, after the interview the recruiter said I did well and tried to sell me the team position in a hour long telephone conversation. I resisted and said I wasn't sure about it. Then they disappeared for a week, came back, invited me in again (after like 4-5 days) to speak with the manager of the project I did not like. Went spoke to him. Liked it all even less. Nobody really seamed to care I preferred the other team. Eventually they disappeared for another week or so. I ended up accepting another offer. They contacted me again but said I wasn't interested anymore. All this took like 1 month a 1/2. Too much in London, for a company like this. They really think they are major like google, apple... and can take the luxury of multiple interviews across a huge time stretch.