The interview process in general was fairly well-coordinated. I was interviewing for Sr. Product Mgr role at AWS (EC2 and S3 teams). The process for interviewing at AWS might be a bit different than for the other groups at Amazon, primarily because they see AWS as a start-up within Amazon and are trying to keep that start-up atmosohere (at least so I was told). Also, they recently introduced a new step for product managers in the interview process: before you are invited to the onsite interview, you need to submit a writing sample which tests your communication and verbal skills. But all in all, the interview process and questions were very similar to what you find here in the reviews - plenty of pricing questions and the majority of the interview is behavioral. I had two phone interviews before being invited to the onsite 1-1 interviews in Seattle. The phone interviews was fairly straight forward, 10-15 min about your background and fairly easy mini-case to test your problem solving/analytical skills (keep in mind that the case is most probably related to one of the business problems amazon is currently facing, or "how can you make it better" sort of problem - again, expect lot of pricing questions!).
After the phone interviews, I got invited to Seattle for onsite interview, which is actually when I changed my opinion about Amazon: I had 7 back-to-back interviews from 9 until 4 which is pretty exhausting ( I didn't even get a lunch break!). I know that amazon is trying to stress-test the candidates, but 7 back-to-back interviews without lunch is just not OK! Also, keep in mind that I went to a top 3 b-school and interviewed with wallstreet banks and was in management consulting before and nobody does 7 back-to-back interviews with no break in between - It is just stupid and I am not sure what they are trying to evaluate. The folks I have met with weren't really that intelligent, but everyone was snobby and thought that they are top smart because they work at Amazon - one of the Director I was talking to couldn't even differentiate between the terms "market penetration" and "market size" and I was pretty disappointed at the intellectual caliber of the people I met. Some of the VPs I spoke to came into into the interview completely unprepared and you could feel it - a couple of them confused me with the other candidates they are interviewing the same day. I already knew after my second interview, that I will not be a good fit for the company and the rest of the interviews during the day proved it. Also, they try to imitate the McKinsey-interview process (I worked for McK) during the onsite interviews, but McK is extremely structured and does it with perfection, and you can feel that amazon's process is just a very cheap imitation of that model - you shouldn't use McK model if you are unstructured and can't execute it!
All in all, it was an interesting experience, but I don't think I would have gone to AWS even if I would have got the offer - they are very unstructured and unorganized who think they are the smartest(which is NOT true, they don't even come close to the folks I've spoken to at Google!)