Quite frankly I've never seen people use AWS offerings for CI pipelines, I wonder if other products (Code* family) are any good - can anyone comment on them? I've only used CodeCommit once during a hackathon, and it seemed rather basic.
That said, when you've setup a build/pipeline, it mostly just works as it should.
I also prefer externalizing the CI/CD process with Jenkins or Spinnaker-based setups.
You can get much better results almost anywhere else.
I appreciate this is a bad reason to recommend a service, and am not defending it. Just explaining why we wound up using it.
The service itself is not horrible, but like every other AWS service, I felt like I was definitely not in the target market: some easily implemented feature was left out and the configuration space easily allowed you to specify things that weren't covered in the (very) thin documentation and seemed to behave unexpectedly.