In practice, it comes across as something of a hybrid of Github and Bitbucket's UI-- the top gobal navigation bar and sidebar navigation structure are very sim

In practice, it comes across as something of a hybrid of Github and Bitbucket's UI-- the top gobal navigation bar and sidebar navigation structure are very similar to Bitbucket's, but they take Github's "code first" approach to displaying repositories (the first thing you see when opening a repository in Gitlab or Github is the source tree; on Bitbucket the first thing you see is the readme and a summary of bug reports). It's probably also worth mentioning that Bitbucket's also in the process of a massive navigation redesign; the "new" Bitbucket eliminates the top global navigation bar, moving some of its elements to a new sidebar (beside the context-specific sidebar) and eliminating much of the global navigation elements completely from repository pages (want to go directly from a repository page to a team or project page? You can't unless it happens to be in the repository's breadcrumb bar.). This is about as much of an improvement as it sounds like. (Sorry, no screenshots of the new Bitbucket UI since I can't quickly produce one that doesn't have private info in it.)