I've used both, and ECS was definitely the bigger pain. I deployed to and managed an ECS cluster for 8 months; the lack of replicability locally (which sucks for testing and CI/CD), the opaque and limited management options, and the lack of community interest / discussion all turned us off.
I think hosted kubernetes was easily the better option for us.
Another alternative for managing containers on a cluster of machines is AWS ECS. It has been around for a while and integrates really well with other AWS services (e.g. Cloudwatch, ALB). Unlike Kubernetes the scheduler is proprietary, but the agent running on individual instances is open source.
We've been using ECS for a while together with Terraform for managing the whole infrastructure in immutable and declarative way, and it has been great so far.