I used gerrit and zuul a while back at a place that really didn’t want to use GitHub. It worked pretty well but it took a lot of care and maintenance to keep it all ticking along for a bunch of us.
It has a few features I loved that GitHub took years to catch up to. Not sure there’s a moral to this story.
I feel lucky to have avoided this so far. It’s really not like this on my team. I write a fair bit of code and review a ton of code.