Pros
There is little bureaucracy and a relatively flat hierarchy. Many members of senior management have a technical background and are very intelligent. They are also open to ideas and respectful of other employees. One of Amazon's corporate values is frugality which usually leads the company to avoid and cut unnecessary spending such as fancy furniture for senior management, or expensive benefits packages for niche groups. Amazon is a relatively efficient, fun, profitable company to work for.
Kontras
The on call schedule can be a serious burden. It limits the ability to make and keep commitments outside of work at times and can be a drain on an employee's family. They are also starting to lose their young, lean company feel. Process sometimes trumps results.