We were seriously evaluating Matrix as a replacement for Hipchat (about a few months back) through their hosted service modular.im . We didn't end up going for it because it didn't have privacy controls (there's no concept of an org like Slack) and integration with Auth mechanisms like SAML/Google,etc.
I'm glad that matrix.org is now a very different organisation than New Vector. Hopefully it should allow you to focus on polishing the user facing product, Riot.im
I have already used the re-designed Riot - it's nice from a UI perspective, but there's a lot of enterprise use cases that are missing.