I have. I've installed Gitlab and Mattermost on my own server. Gitlab is great but I found Slack was a better product (over Mattermost). Have you tried installing it?
I created a Gitlab account and was planning on using it over Github but their recent data loss scared me off. Is that unreasonable? It worries me just as much to see them buying a company a month after that. Is slowing down unreasonable?
I want to use Gitlab. I like their open approach, but if people just praise them without being objective about it it doesn't benefit any of us. I might just be a selfish and/or entitled user but you'll forgive me for wanting Gitlab to be good. Don't you?