When comparing GitLab CI vs GoCD, the Slant community recommends GitLab CI for most people. In the question“What are the best continuous integration tools?” GitLab CI is ranked 2nd while GoCD is ranked 18th. The most important reason people chose GitLab CI is:
All build setup are stored in .gitlab-ci.yml file, which is versioned and stored in the project. Like Travis do.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro File based configuration
All build setup are stored in .gitlab-ci.yml file, which is versioned and stored in the project. Like Travis do.
Pro Free and open source
All of GitLab CI's code is open source and under the MIT license.
Pro Parallel builds lessen test times
Tests are parallelized across multiple machines in order to reduce test times considerably.
Pro Docker intergration
Good integration with Docker.
Pro Highly scalable
The tests of GitLab CI run parallel to each other and are distributed on different machines. Developers can add as many machines as they want or need, making GitLab CI highly scalable to the development team's needs.
Pro Quick setup for projects hosted on GitLab
Since it uses the GitLab API for setting up hooks, the setup of GitLab CI for projects hosted on GitLab can be done in one click.
Pro Kubernetes integration
Easy to test and deploy on Kubernetes.
Pro Native support for pipelines
GoCD supports pipelines natively. This way you can build your projects by pipelining them.
Pro Good traceability of what contributed to a given artifact
GoCD's LEAN value stream UI helps all stakeholders focus on efficient product delivery (instead of collections of technical tasks).
Cons
Con Not lightweight
Not a lightweight solution, demanding and memory hungry.
Con Cost
Larger projects will need upgraded version
Con Security risks
Con Windows not supported
No Windows support, but it's possible to use a Bitnami stack.
Con Need Scripts for everything
Almost all operations are shell based, they are not configurations possible, your CI is as good as your scripting

Con Does not offer many plugins
Since it's relatively new and not very popular, there are few plugins available in GoCD.
Con Somewhat tricky to setup
