Pros
After previously being at Fortune 500 company, the single biggest thing that stands out is how empowered you are - right from the beginning. Things move incredibly fast. With the growing size and reach, you have the opportunity to move most anywhere in the world. Additionally I left Amazon after two years to work on a project outside the company. After a year away and standing up what I'd left for, I came back to Amazon and have continued to stretch myself and feel honored to be able to do so.
Cons
The ability to ruthlessly prioritize and communicate expectations is critical. Without it, you could feel overwhelmed. I often tell people that, "Amazon will never tell you, 'you're good for the day, head home - good job!'". Frankly, I like it that way because it creates an environment where focused and driven people and run free without bureaucracy and red tape. But it isn't for everyone ...and that's ok!