It's not that bad. If you only use GitLab for the git repo management purpose and already had other tools for CI (e.g. Jenkins, CircleCI) and project management (e.g. JIRA) then GitLab CE works perfectly fine. The only thing that I wish would be in the CE version is the ability to approve merge requests.
6 years ago I was trying to setup GitLab CI. From memory, it was a bad experience since there were missing or incorrect pieces of crucial information. At the end they were figured out but if the status quo is still the same I believe it would not be easy to automate a rebuild.
Hello, GitLab employee. I definitely hope we've matured a lot since 6 years ago! In early 2015 there were still only 9 employees [1] compared to almost 900 now.