We went Skype => Slack => MS Teams => Mattermost for our developers. If Teams wasn't such garbage at basic things like markup and pasting screenshots, we might still be using it for everything.<p>I had no real concerns with Slack from a development perspective. We simply wanted to try a unified messaging platform for the whole enterprise (our non-developers much prefer Teams/Skype for some reason). That experiment failed for our developers, so we now maintain 2 stacks - Teams for company-wide communications, and Mattermost for developer-intensive communications (or anyone else willing to teach themselves how to use a new thing).<p>Mattermost has proven to be an incredible solution for our development duties. I just installed it directly on a EC2 t3.small instance and we've been using it for about 9 months now without any pain points to speak of. I literally haven't touched that machine since I turned it on day 1. To be fair, we are <10 developers, but we get pretty heavy with the screenshots and json/code dumps throughout the day. We did make some compromises with authentication in favor of expediency of deployment, but it's really not a big deal for our developers to keep track of their LDAP vs their mattermost credentials. If someone complains enough I'll spend a few hours to hook up LDAP too.