I would rate the scalability a nine out of ten. We use it every day.
AWS CloudFormation automates infrastructure management, reducing errors and standardizing deployment using templates. It integrates well with AWS, streamlining provisioning and supporting effective change management. While efficient in input handling and versioning, it lacks support for other cloud vendors and has issues with cross-account references. New AWS services often delay in getting full support. Provisioning large environments is slower than Terraform, and error handling, particularly with circular dependencies, needs improvement.
