Pros
You get to work with a lot of smart, talented people. Amazon has a fast paced environment that encourages innovation. You can work on a lot of interesting projects and get to try out new ideas.
Kontras
Most people at Amazon will have a lot of managers during their career. A colleague of mine had 13 managers in 4 years. Your experience at Amazon largely depends on your manager. If you have a bad manager, you will have have a bad expeience at Amazon. Poor managers do not give any feedback to their direct reports and emphasize face time over results. I know of many people whose manager actively blocked their transfer to another group. Going to HR also does not help as they will always take the side of the manager. Also, you should expect to work long hours at Amazon.