Plenty of work is being done in terms of performance improvements, and almost every release features a large set of improvements. A list of all performance related merge requests that have been merged can be found at https://gitlab.com/gitlab-org/gitlab-ce/merge_requests?scope....

If you'd like to help out you can read up on the contributing guidelines at https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBU....

Alternatively, any issues with data on what is slow and how these patterns can be reproduced is also greatly appreciated!

We're working hard on making GitLab.com faster (where I also made the gifs) [0]. If you're running your own instance, it should be fast.

[0]: https://gitlab.com/gitlab-com/infrastructure/issues/59

Yeah, the feature set might be good (better than GitHub, I don't know), but every time I try GitLab or use Bitbucket, they're just so sluggish compared to GitHub it puts me off. Edit: I just tried GitLab again, and it looks like they've made good progress in this area -- still seems significantly slower than GitHub, but it's no longer dog slow to just browse source code.