Prós
Great company filled with amazing and intelligent people. You learn and grow so much just by being within Amazon. The culture and rigor around their process/standards is the highest in the industry. You will never experience growth and learning the way you can at Amazon.
Contras
To truly succeed and have fun at Amazon: You have to be ready to compromise your work/life balance and commit to your work because you are going to be competing with everyone else in the company who is facing the same choice. The company is filled with passionate people who are willing to make this choice. The people who succeed at Amazon have made this commitment but they are also working with the best of the best on amazing projects, so the commitment is not inherently bad.