I went through 4 rounds, phone screen, two different phone interviews, and the final loop which was two days and a total of 6 interviews. I personally had a great experience, my Amazon recruiter great and very responsive. They provide so much information and a nice amount of time between interviews so you have plenty of time to prepare. While the experience as a whole is taxing, I enjoyed the uniquness of it. For a company as large as Amazon, I was impressed with how seamless the proccess felt.