Pros
You'll be surrounded by some of the smartest people around which allows growth and development. Amazon strives to be innovative and say ahead of the curve which offers a level of pride and fosters drive in employees to continue pushing to be the best. There are a lot of opportunities to work in different departments. I don't think anyone is ever bored working for Amazon as there's always more than enough work to do. Many projects are really cool and exciting to be involved in.
Cons
Amazon is a tough place to work if you need a work-life balance. I sometimes feel guilty when I take vacation or am ill because of the things I miss when I'm gone. That said, I'm never 100% out as my e-mail is available on my phone and I'm always connected. Interdepartmental communication could be improved. Each team operates somewhat separately and communication is almost non-existent until there's an emergency.