This question comes up in almost every infrastructure conversation we have. Here's our actual opinion, not the vendor-neutral non-answer you usually get.
Start with ECS unless you have a reason not to
For 80% of workloads, ECS on Fargate is the right answer. It's simpler to operate, cheaper at small to medium scale, and deeply integrated with AWS services. If your team doesn't have a dedicated platform engineer, ECS will serve you well for years.
Kubernetes is an operations commitment. It gives you power and flexibility, but it extracts a significant operational tax. Cluster upgrades, node management, networking complexity, RBAC, custom resource definitions — it's a full-time job to do properly.
When Kubernetes wins
- Multi-cloud or cloud-agnostic requirements
- Complex workload scheduling (GPUs, spot instances, bin packing)
- Large teams with dedicated platform engineering capacity
- Custom operators for domain-specific automation
- Existing Helm chart ecosystem you need to consume
When ECS wins
- AWS-only deployment (which is most startups)
- Serverless containers via Fargate with no cluster management
- Deep integration with ALB, IAM, Secrets Manager, CloudWatch
- Small-to-medium teams without platform engineering headcount
- Faster time to production on a new project
The honest answer
Choose the option your team can actually operate well. A poorly-run Kubernetes cluster is worse than a well-run ECS cluster in every measurable dimension. Complexity is a debt that compounds.