Amazon

You'll be working with systems that function on a scale that very, very few other companies have to worry about.

Every year, they have to push the envelope to survive the Christmas season without melting down. It's something that you don't get elsewhere.

On-call and operation load is a significant part of the job, but not a significant part of the job description. There is little effort to retain or reward employees.

Employees are given responsibility over projects, but not the authority to make changes. It's a very top-down company, and sadly, there are often cases where a project is redesigned at the last minute because middle management didn't get sign-off from senior management, or senior management was flakey.

There's no institutional memory because of the high turnover. This means that people are reinventing the wheel a lot, often in parallel.

There is an assumption that employees are perfectly okay with giving up a major chunk of their lives to the on-call burden, or to rush to meet an arbitrary deadline for some VP's pet project that will then be killed right before launch.

Amazon does a good job of recognizing employee accomplishments for good work when things are normal, but they are pretty lousy at recognizing and rewarding employees when situations are crappy. There's no reward to compensate for particularly nasty on-call rotations or for working overtime.