If you're already invested in ECS it's a different story, of course.
AWS is committed to improving both ECS and EKS. You can see our public roadmap with many in progress improvements for both container orchestration platforms here: https://github.com/aws/containers-roadmap/projects/1
Feel free to add your own additional suggestions, or vote on existing items to help us prioritize what we should work on faster!
Some of the problems we're seeing is task placement and waiting is too hard (we had to write our own jittered waiter to not overload the ecs api endpoints when asking if our tasks are ready to place). Scaling the underlining EC2 instances is slow. The task definition=>family=>container definition hierarchy is not great. Log discovery is a bitch.
Are these all solved under K8S? I've no experience with kubernetes, but if so, might need to rethink where we run our containers. ECS was just so easy, and then so hard.
Do you mind if I ask how long this takes right now with you and how long you expect it to take to be fast?
It's significantly more complex to host kubernetes infrastructure, and EKS is significantly more expensive.
ECS would be a first choice, with EKS a second choice if my needs dictated it (perhaps a hybrid or milticloud scenario).
To clear up the confusion on the relationship between Fargate and ECS, think of Fargate as the hosting layer: it runs your container for you on demand and bills you for the amount of CPU and GB your container reserved per second. On the other hand ECS is the management layer. It provides the API that you use to orchestrate launching X containers, spreading them across availability zones, and hooking them up to other resources automatically (like load balancers, service discovery, etc).
Currently you can use ECS without using Fargate, by providing your own pool of EC2 instances to host the containers on. However, you can not use Fargate without ECS, as the hosting layer doesn't know how to run your full application stack without being instructed to by the ECS management layer.
Which is why, I assume, Fargate is now listed as an integral feature of ECS on the product page.