Corporate messaging apps are very special. quite possibly they are the most important app or even technological decisiom any company of any size or stage can make. They decide how people communicate and collaborate. Small changes have huge ramifications.
Thah said, I am support Matrix bigtime and it is worth noting that the French government uses them, how that has impacted the French gov/people I have no idea.
Good stuff:
* OIDC for authentication (or CAS or SAML or LDAP etc)
* "Spaces" to organise all your rooms across the organisation (and overlapping organisations)
* Audit bot for compliance (a bolt-on in Element Enterprise)
* "Group Sync" to bridge space membership and permissions to Active Directory (a bolt-on in Element Enterprise)
* Loads of clients for different environments, and a really nice open API for writing new ones and bots and integratinos.
* Bridges to existing corp systems like Slack and Teams to help do a rolling migration.
* Great E2EE voip/video confs via Element Call (and Video Rooms) these days.
* Federation, obviously, to work with other deployments within or between orgs, if you want.
Bad stuff:
* E2EE makes it hard for new users to see history when you join encrypted rooms. We're working on this currently.
* Not as many integrations as Slack or similar yet - we really need to provide slack-compatible webhooks out of the box so we can leverage existing integs.
* E2EE search doesn't exist on mobile yet
* Lack of multiaccount makes juggling corp & personal accounts a pain.
In the hosted version they provide bots for doing the sort of auditing/logging things you are going to need and the support has been excellent.
Overall, better than Teams :)