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.