When comparing Buildkite vs GoCD, the Slant community recommends GoCD for most people. In the question“What are the best continuous integration tools?” GoCD is ranked 18th while Buildkite is ranked 23rd. The most important reason people chose GoCD is:
GoCD supports pipelines natively. This way you can build your projects by pipelining them.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Very easy to set up
The web UI allows writing a build script inline, running a script from your repository, or creating a whole pipeline. Docker support is built-in.
Pro Allows parallel jobs
Buildkite allows you to configure your build in order to run parallel jobs and obtain considerably faster results.
Pro Scheduled builds
Run builds on a cron-like schedule to rebuild a master branch or run an import process.
Pro Run your own build servers
Run an agent on your own servers (AWS, etc) so that you have control over what your builds can access.
Pro Intergrates with VCS
Integrates with GitHub, GitHub Enterprise, Bitbucket, Bitbucket Server, GitLab, Codebase, or any custom Git repository.
Pro Affordable
One plan that gives you everything at a reasonable price.
Pro Plugin support for docker and docker-compose
Pro Concurrency control
Make sure only one deploy build runs at a time with concurrency control.
Pro Config driven build process
While you can define your build process in the dashboard, you can also run it from config files in the repository.
Pro Responsive support
Support respond quickly and listen to feedback.
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 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
