Pros
Amazon is a fast paced environment that allows one to learn a lot from developing large scale software. The company does care about it's customers. You can often end political arguments by focusing on the customers. You will work with a bunch of smart workers who are very talented. The work life balance is decent, but it also depends on the team you are on. The senior management has been pretty good at listening to people below them, and giving the workers the proper support they need. Senior management also has a pretty good idea of how to progress the team for the future.
Cons
The biggest down side is carrying a pager around. Depending on your luck of the draw, you could be working on holidays. Some teams within the company are not as responsive to taking ownership. i've also seen many talented SDE 2's that have worked at Amazon for many years that have not been promoted to SDE 3. It seems that jump is a huge roadblock for the SDE career path. The health benefits are not that great when compared with some other companies. Also, the company's only perk is a 10% discount towards Amazon.com purchases up to a total savings of $100 a year. Even if one of the company's core value is frugality, this is too frugal.