Normally I'm a sucker for irony, but when they sent me an auto email a few weeks later asking _me_ for feedback (ie, a survey on the hiring process), I didn't find it immediately funny.
Those made me wonder if it wasn't for the best.
I'm not hating on Amazon but their recruiting process is by far the sloppiest of all big tech companies.
What I meant is that I can't recall any feedback like "personable, but algorithms needs work" or "code too messy" or "couldn't answer domain questions" etc. Just a general "sorry, please try again later."
To be fair, this was a verbal conversation from 7 months ago, so it may be there was something like that but I was too preoccupied with the bad news to write it down.
I wasn't given anything specific, but I was given fairly strong hints like "I think you know that the 3rd and 5th interviews were your best". I was told that they thought my communication was clear, and that while they didn't have any issues with my code, I could have been faster and a bit more fluent converting my solutions into code.
Probably boils down to what your recruiter is willing to give you, and how much you can correlate what they say to your interviews.
All in all a pleasant experience, though the luck of the draw part became very obvious. Were I to go for it again, I know exactly how I'd prepare for it. The key (in my experience) is to be able to hammer out that first coding problem in under 25 minutes. If you get to the 'second stage' where you're chatting to your interviewer and trying some additional toy problems, you're doing well.
In that case it's true, you generally don't get any feedback after you interview at big tech companies. I would recommend to do a mock interview to prepare and get honest feedback.