As far as I can tell, working in the AWS teams is perhaps the best software engineering place to be at Amazon (e.g. note Tim Bray's joining the Vancouver office.). The positivity from there I've seen echoed by other diverse sources, so unlikely to be just kool aid.

Everywhere else, stay away, unless it is something you have a very very strong passion for. (Perhaps the Games teams might be another AWS like atmosphere in the making, hard to say yet). Don't get bait-and-switched with AWS buzzwords, make sure it is AWS doing the hiring.

From my experience working for Amazon, they seem to grind engineers down, so they are regularly churning through a constant supply of graduates to keep employee numbers up. So a large chunk of engineering is new to 2 years.

Stack Ranking (the cross-over of staff between Amazon and Microsoft in Seattle means the same people drawing up employee performance processes. They may insist it isn't stack ranking, but looking at how the review process works is inescapable that the nastiness of stack ranking is present)

Edit: there are a handful of genuinely good engineering teams at Amazon, but their ability to make a positive impact is tainted by the volume of garbage that surrounds them.