Pros
At Amazon innovation and efficiency are prized. Amazon's customer obsession is a big positive. The company prefers to invest in long term decisions which are positive for customers over short term decisions which may give the company a temporary boost. While no company is a true meritocracy, Amazon does a great job of rewarding performance and delivery of results. You will also get to work with very smart people at Amazon. There's always an opportunity to learn from your peers or management. There are many mechanisms for feedback and your job will have a lot of visibility and potential for impact.
Cons
Amazon is a great place to work but because people are quick to give feedback and/or share an opinion on your work you really need to have a thick skin or be able to take critism well.