GitLab vs Gitless: What are the differences?
Developers describe GitLab as "Open source self-hosted Git management software". GitLab offers git repository management, code reviews, issue tracking, activity feeds and wikis. Enterprises install GitLab on-premise and connect it with LDAP and Active Directory servers for secure authentication and authorization. A single GitLab server can handle more than 25,000 users but it is also possible to create a high availability setup with multiple active servers. On the other hand, Gitless is detailed as "An experimental version control system built on top of Git". Gitless is an experiment to see what happens if you put a simple veneer on an app that changes the underlying concepts. Because Gitless is implemented on top of Git (could be considered what Git pros call a "porcelain" of Git), you can always fall back on Git.
GitLab and Gitless are primarily classified as "Code Collaboration & Version Control" and "Version Control System" tools respectively.
GitLab and Gitless are both open source tools. It seems that GitLab with 20.1K GitHub stars and 5.33K forks on GitHub has more adoption than Gitless with 1.44K GitHub stars and 76 GitHub forks.