Mostly horrible

After 3 years at Amazon, here's my experience:

Amazon has a few really well run teams and a lot of very badly run teams. The result is people's experiences are all over the board, with the only common element being that most people burn out after a year.

Amazon is deliberately built to be Darwinian. The "strong" survive and the "weak" perish (metaphorically speaking, but sometimes the toll of the stress makes this literal too). It's a kind of crucible that will force you to develop a hard edge, if you can survive. It's simply not a pleasant experience.

Annual review ranking is a horrible practice rife with favoritism. It's not data-driven. It's not frugal in wasting a lot of time and effort firing and replacing competent people who aren't politically "successful".  The entire process has more defects than virtues and results in a mostly horrible experience for employees and the resulting 90% of staff leaving in less than two years.