I agree. I too work with a self-hosted Gitlab instance daily, and the UI is neither horribly bad nor horrendously slow. The interaction design and user experience could absolutely use some work, but I feel Gitlab has been moving in the right direction with this.

The navigation is still a bit convoluted, but has gotten better. There are still some issues of nested navigation menus and difficult to find pages. As far as page speed goes it has gotten better and they are actively working on this.

As long as the rate of improvement is as good as it is I see no reason to switch to another solution. Especially seeing how the community edition is free and satisfies basic developer needs.

Gitlab is also the only code repository service which integrates CI jobs and statuses as well as a front-end for a self-hosted docker registry. Absolutely a killer feature!