Could you share an example of what you went wrong?
The Mattermost server has around 59% automated test coverage, our community does over 120 hours of manual testing prior to each monthly release, and we're constantly striving to improve.
Here's a recent review of Mattermost's quality levels, from someone who left Mattermost and then returned, concluding Mattermost was the leading solution: http://www.akitaonrails.com/2016/08/13/choosing-mattermost-o...
If your experience is different, we're highly interested in knowing how we can improve.
So far, we ranked #1 is Mattermost and other is Julip.