a) Gitlab.com is ridiculously slow. Even the CEO admits they failed to invest in it.
b) You can't disable features you don't need so you end up with a sidebar full of Kubernetes and Security features for a Git project dedicated to documentation.
c) Staggering amount of open issues and merge requests so you feel discouraged from even raising anything since it just gets lost in the weeds.
d) On the main Git project screen there are 15 buttons. Including again ones for "Add Kubernetes cluster" or "Add License" which you can't remove or hide even though it's irrelevant for 99% of Git projects.
e) Feature set and billing are all over the place. It has great project/issue management but in order to get say roadmaps you need to have everyone in your team on the $99/month plan. Even though they aren't developers. So in some cases Gitlab ends up being much more expensive than Jira + Github.
I could keep going. But Gitlab is an example of a company that is moving too fast and needs much better product management. I would take Github's more deliberate approach any day.