Earlier quoted context omitted.
I believe gitlab's UI has gotten better lastly. Nevertheless, if 99% of the value provided by github comes from their interface, should we remember how much time they needed to implement the "+1" counters on messages?
Agreed. Gitlab's interface is better. Especially the issue board. Throw in their fully-integrated CI platform and container registry basically makes Gitlab a winner.
The GitHub ecosystem will be the biggest hurdle for GitLab to overcome. (Disclosure - I work at ZenHub)