A complex and lengthy series of phone interviews over the course of several weeks, plus a written assessment, a final series of face to face interviews, and then more phone interviews. No feedback, other than "the next stage is....", "you are required to...".
90% of the interview questions were behavioural "give an example of a time...." with occasional references to the actual work that would be involved. A couple of tricky maths questions got thrown in.
Be prepared for interviews to end quite bluntly, especially if the interviewer has another meeting; it doesn't automatically mean you failed. It was good to be flown out (economy, expenses paid) to their European hub site, but you're independant and won't be "hosted". There was no real welcome or tour of the office, and you may be expected to go out and navigate the city (and the foreign language) on your own for a few hours at lunchtime, when they have nothing else for you to do. Take a phrasebook!
The whole process expects you to be an "Amazon fanatic" and absolutely on top of your game the whole time. No attempt was made to impress potential candidates; questions about what they found enjoyable or fun seemed to throw a couple of them. Some of the interviewers were more engaging though, and you do get an interesting insight into how they think about their business.
They make a big deal about their "leadership principles" (be prepared to quote them in interview); but the culture seems intentionally obsessive and agressive (they call it "peculiar"). Some of their working practices are not as mature or well crafted as you might expect. A few of the leaders I spoke to, especially in operational roles, seemed quite stressed and distracted. I withdrew from the process after I was hit with another two weeks of silence after the final interview.
Overall, the interviews were quite agressive and clinical; not geared towards finding genuine, good and engaging people. You do get some interesting peeks "behind the curtain", and they're a pretty sucessful brand that many presumably enjoy working for - so go in well prepared, and with your eyes open!