1 phone screen and 5 rounds of onsite interview.
Pretty smooth and positive type interviewing i.e. no artificial, made up questions. No trick questions and no intent to grill for pleasure.
Very objective questioning.
HR recruiter actually preps you on what to prepare, how to prepare before going to the onsite interview.
Interviewers were very respectful of my time and made a lot of notes.
I did a lot of whiteboarding to set project context, explain situations, project plans etc. and it was all conversational style.
They take you out for lunch and make it clear that it is not to judge you. It is to relax you and allow you to ask anything about Amazon.
Also they love the writing culture and make you write an essay on a specific issue, before you come to the interview. They don't necessarily review it in the meeting, but do review it offline to make sure you fit into the writing culture.