GitLab has a page comparing it to Atlassian Bitbucket: https://about.gitlab.com/devops-tools/bitbucket-vs-gitlab.ht... There are also other comparison pages with other DevOps tools linked from this list: https://about.gitlab.com/devops-tools/ Even though that content is managed and served by GitLab, if you feel there are inaccuracies or a tool missing, you can propose edits through various channels.

I am not sure on how Bitbucket compares because I haven't tried GitLab in a while, but we use Bitbucket at work.

Bitbucket works well and the Pipelines functionality is a life saver for us. I wish I started my projects differently though. After bringing on my first employee it takes a lot of reorganizing of the projects to get them access to it. That's not an issue with Bitbucket though... just a cautionary tale.