Pros
First of all, it starts with the people and one of the Amazon Leadership Principles - Hire and Develop the Best. The interview process is intense, but it ensures the people you will be building with are of the highest quality. People here have been very supportive of me in my first two months as I am coming up to speed. AWS is the obvious leader in the cloud computing space, and maintains their edge with relentless innovation. If you like working on cool stuff in the cloud space this is the place to be.
Cons
So far I haven't seen anything about the company or culture that I could call a detractor, with the possible exception of compensation is highly tied to stock. I took a meaningful pay cut to come here, and people assured me it would balance out with the RSUs... I guess we will see about that as shares vest.