Pros
You have a lot of ownership over your work. There is a lot of freedom to set your own goal and exercise best judgments. There usually is not a lot of micromanaging going on at the company. You are usually given a general goal or a vague set of problems, and you are expected to exercise best judgment to resolve and/or achieve them. Additionally, there are a lot of smart people at Amazon, and there are some great technologists here to learn from as well. Amazon is basically like a 10+ years-old and multi-billion dollar start-up, with all the good and bad that implies.
Kontras
It's a very competitive and chaotic environment to work. You never know what's going to happen tomorrow, and the ownership of your work often implies very long working hours. There is also a severe lack of process or usage of industry best practices. The company culture also encourages hackers to slap things together to meet short-term objectives without taking into consideration of long-term impacts. Some groups also falls into a dark spiral, where the service the team owns are buggy, thus requiring high operational burden, i.e. being paged at 3am when something is down, which burns engineers out, which leads to even higher operational burden. It's a vicious cycle.