May I ask why you are planning to join Amazon? It's reputation for being a bad employer is well-established and known in the tech community.
If you're skilled enough to get through an Amazon interview loop, you could also get a job at a company which actually respects its employees (Facebook, Google, even Microsoft).
I love the AWS platform, I find the entire thing very elegant. I wanted to move away from software development and get into more high level stuff (hence the SA role), and I'd rather join a company where am passionate about their products.
I have friends working in AWS, and so far none of them have been complaining about work life balance, so am assuming that it's different from the retail side.
Well I do hope it's not as bad as it's portrayed. I do want to see my son grow up (he is turning 2 years old).