We have gitlab set up at work for our small team, but we never use it. We just do regular old git operations from the CLI and use e-mail and Bugzilla for issue tracking. I've wondered if maybe there was a feature of Gitlab we're not using that we should, but so far nothing's stuck.
We do merge requests by hand (there's several ways to do reviews/merges with git CLI), and communicate on bugs or e-mail threads. Oh, and I forgot to mention before we integrate git with Jenkins for CI and testing/reviewing/merging.
