Honestly I didn't have a good experience with ECS (Fargate) - I remember I had to write a ton of CF deployment scripts+bash scripts, setting up a private AWS docker registry, having a terrible time debugging while my CF deployment always failed, deploys taking forever, finding out that AWS is too miserly to pay Docker to use the official repo so they are stuck on the free tier, meaning sometimes deploys would fail due to Dockerhub kicking the AWS docker agent out etc. It had limitations like not being able to attach a block volume to the docker instance, so overall I remember spending a week setting up the IaC for a simple-ass CRUD app on Fargate ECS.

Setting up the required roles and permissions was also a nightmare. The deployment round trip time was also awful.

The 2 good experiences I had with AWS was when we had a super smart devops guy who set up the whole docker pipeline on top of actual instances, so we could deploy our docker compose straight to a server in under 1 minute (this wasn't a scaled app), and had everything working.

Lambda is also pretty cool, you can just zip everything up and do a deploy from aws cli without much scripting and pretty straightforward IaC.