For us it's the following reasons: * It's more cost effective to place all the services on one cluster. As containers can share the instance resources it's eas

For us it's the following reasons: * It's more cost effective to place all the services on one cluster. As containers can share the instance resources it's easier to increase resource utilisation (not true w/ Fargate though). * Support for new features on EB can be quite delayed. Eg. we need support for ALPN policies, it's a recent feature and it's not even in CloudFormation yet. With ECS we just manage the LB directly and we can do everything the API allows us to do. * More granular control. Eg. during rolling updates we can decide a floor to how many containers are active at a given time (many others things like this). * Integration w/ SSM and Secrets Manager. * Better IaaS support (with EB everything happens in configuration files outside of Terraform or Cfn resources).