If your architecture is amenable to storing files in S3, do. (And if it's a web app, ideally you'd serve them directly, via CloudFront.) EFS first and foremost

If your architecture is amenable to storing files in S3, do. (And if it's a web app, ideally you'd serve them directly, via CloudFront.) EFS first and foremost will take away a huge amount of pain when trying to make filesystem-dependent legacy applications more reliable.