Pros
I have worked as an engineering manager at Amazon for nearly five years. I don't think I have learned this much in the same period at any prior point in my career. Employees at Amazon are given a lot of ownership over an area of their product/service. In my opinion, Amazon is one of the best places to join early in your career since people are stretched to own large scale projects that help them grow & develop. I have also found Amazon to be very flexible when it comes to my work schedule. I am able to work a day or two from home when needed, leave early one day and work late another day to make up for it. As long as you are doing great work, people are very flexible.
Cons
I am still very happy at Amazon and don't have any major cons to report. One of the biggest things to consider when joining the company is that it is a very decentralized place. It is possible you could land in a team that is not a great fit for you. It was good to see Amazon revamp its internal transfer policy recently allowing employees to transfer when they are ready instead of waiting a mandatory 1 year.