My BI team is looking for a source control solution. Based on your experience with Azure DevOps and Bitbucket what would you say are the pros and cons of each, and if you had to choose based solely on source control which do you believe is the better solution?
If you are looking for CI, BitBucket is not the preferred solution - it has many limitations that Azure DevOps does not have. That being said, GitLab is probably a superior solution to either as it has a very sophisticated and flexible CI solution and you can even run your own CI workers if you need access to resources that aren't available on the hosted service: such as specific hardware, very long run times or licensed software.
Other than that, if you are only interested in source control, and specifically git - either will be a good offering as well as quite a few others. You do need to make sure that the software you plan to control is a good fir for git - specifically, if you are looking to store large data sets (I'm thinking BI, yes) as a source of truth, git will be a poor choice and you should look for hosting based on Subversion or Mercurial.
If you need just the source control feature, there aren't much difference. Azure DevOps has slight advantage since it has TFVC besides git. But, if you need some other features, like CI/CD, ticket/task management, etc. Well, that is completely another thing. For example, it is very easy to integrate BitBucket with JIRA. You could even combine BitBucket source control with Azure DevOps pipelines for easy CI/CD.