When I was at Google, I talked to people who have worked at both.
The general gist of it was: while one got treated better at Google, you got more done -- and had more freedom to choose how to do it -- at Amazon. So depending on the team, potentially higher job satisfaction.
I don't know if that's still the case. Personally if I'm going to sell my soul and work on stuff which isn't my personal passion, it's going to go to the highest and best bidder... but I will admit after 10 years at Google, the slow pace and boredom got to me enough that I quit. Maybe I would not have done that if I'd felt more emotional attachment and productivity in my work, and maybe a place like Amazon could have provided that. But I've heard too many dark tales. (I sure miss that level of money.)