Avantages
AWS gives its engineers a tremendous amount of responsibility and empowers them to do whatever it takes to meet customer needs. As a Senior Software Development Engineer you are responsible for requirements analysis, architecture design, software design, project management, software implemention, testing and operations for teams of 4 - 20 engineers. The services you are responsible for could have thousands to hundreds of thousands of customers and involve internet scale parallel computing problems.
Inconvénients
There is no net. At AWS you have the opportunity to create highly visible systems that many well known companies build their business on. If you break something you created, it's on you to discover the problem, diagnose and fix it before it causes pain for customers. This can be stressful at times because you effective "own the business", at least from a technical perspective.