I interviewed a few weeks back with Amazon for a level 7 TPM position.
1) It was hard to get one person to be the central POC. I was contacted by multiple recruiters for various positions, started the interview process for multiple teams and for multiple position types. It took a while to get sorted.
2) Recruiters and interviewers are overall very professional. It is a well-oiled machine.
3) The interview is difficult, as expected - more in line with the interview I would have given to a Sr Director in other tech companies.
During the final interview cycle, I talked to 7 or 8 people, at the Principal level or above, all the way to VP. It is an exceptionally long day. Add these 8 hours to 3 or 4 preliminary interviews with the recruiter, screeners, etc. and a written essay.
Lots of behavioral questions and case studies, a few design questions. The technical questions were quite general and cater to high-level design patterns, rather than specific implementations. I expected them to be more difficult and focused.
The discussion was completely one-sided and open-ended. You must think on your feet. Expect very little feedback from the interviewers, even when prompted for clarifications - it was hard to gauge if I was answering their questions or not. You will ramble in the dark most of the time. Expect relentless focus on details - you must give specific examples. Expect to talk 90% of the time and only be given a couple of minutes of time at the end of each interview for your questions.
Amazon focuses enormously on their leadership principles - the distinct impression was that, if hired, I would be constantly judged on these criteria and expected to adhere body and soul to their corporate principles.
Overall, while all interviewers were polite and extremely professional, they also felt cold, almost mechanical. The focus here is on relentless efficiency, during job interviews and elsewhere. I interviewed with the Borgs. If one of your criteria for your next job is finding a group of colleagues to work with AND have a beer with, stay away.