Elastic beanstalk (EB) automates the deployment and scaling of applications. We tend to employ AWS CloudFormation to manage these centrally. This gives total control over the application stack.
These stacks are often hooked into continuous deployment systems such as CodeShip. We can quickly instantiate new versions of the entire environment for testing; meaning we can have multiple environments running new features, or different environments for each end clients, managed from a central codebase.