There are a few things that annoy me as a Gitlab user (UX things), apart from the search/responsiveness of the application. Moreover, they improved _a lot_ the installation/upgrade process over these years. I'm expecting big things from you now :)
Anyway I need to say that these guys have been working a lot and deserve much credit. Kudos for you, guys!
One of the things that annoys me most is that the homepage of the repository, where you have the README is not the same where you have a file browser (Perhaps this is Github-biased, but is soooooo much better. Think about it :)