Avantages
I highly recommend Amazon. As an engineer, you have a vast amount of resources and tools to get the job done and the infrastructure is such that you don't have to bug IT to install this and that on your servers (unlike other companies). Your team takes ownership of almost every aspect of your product, so there is a lot of opportunity to improve how it runs with limited red tape. There is a huge emphasis on working on large-scale systems which is both fun and an educational experience.
Inconvénients
As owner of your product, your team will also respond to downtime, most likely with a pager rotation. Depending on your team, you might experience some micromanagement from the Senior Management, but in my experience it happened on an occasion rather than constant basis. Also, sometimes the autonomy that teams have can be detrimental to cooperation. Some times work is duplicated instead of shared properly.