Vantaggi
I was an SDE I at amazon for 1.5 years. The projects are at amazon scale, and the resources exist to tackle any problem. There are many smart engineers who bring valuable industry experience to their designs and feedback. Generally meetings were productive. Career advancement opportunities exist if you are proactive about finding them.
Svantaggi
Those who succeed at amazon have a poor work/life balance. It's a joke amongst the engineers that you can't work at amazon and have a life, and it stopped being funny when I realized it is true. Projects are chaotic and requirements are always in flux, making maintainable code impossible unless you are willing to put in the extra effort to stay on top of everything. I witnessed several accounts of career growth being squelched because of the chaotic culture. Several colleagues of mine were not given well-deserved promotions because either (1) they had been re-org'd and denied the opportunity to complete a design project or (2) people come and go so often that someone with valuable feedback might be gone before they give input.