Too much manager control

After 7 years at Amazon, I can tell tell you that whether you live or die in the Amazon review process is entirely mediated by your manager. In my experience, if your manager doesn't like you, you are out regardless of the quality and quantity of your work.

I've seen people PIP'ed out of the company who were doing the lion's share of their team's work and were liked by their team, but were on the bad side of the manager and were gone in months. Generally I think such people get pushed out with PIPs about their "leadership" which is enough of a fuzzy unmeasurable that there isn't a lot you can do to protect yourself.

If you get hired in, you can't move for a year, so if you are hired under a hostile manager or into a bad team, you have little recourse and once you have a less than stellar review you are further locked into your position and cannot transfer. 

My biggest problem was it was a new manager for every team every year. "Let me do this review on you even though I've known you for only 3 weeks." This is no joke. My last manager knew me 3 weeks and since I didn't "impress him", I got a lousy review. It's final. You can't take it to HR no matter what. I lasted 7 years.