Recs.
Updated
Matrix is a protocol for enabling real-time communication between different service providers.
SpecsUpdate
Pros
Pro Can be integrated with existing communication services
Matrix is designed to support Instant Messaging, VoIP/WebRTC signalling and Internet of Things communication and allows cross-communication between those services. Meaning one person could be using IRC and another Slack for IMs, or one person could be using Skype and another Google Hangouts for videoconferencing.
Pro End-to-end encryption
Matrix features end-to-end encrypted chats which are syncronized accross all your devices.
E2E is implemented in the matrix-js-sdk library and Riot.im client.
Cons
Recommendations
Comments
Flagged Pros + Cons
Con User Interface of stable clients not easy to learn for "non-IT-people"
The user interface of the most popular clients can confuse the test-users in your company (even devs or sysadmins) with lots of verification requests, too many buttons.
Out of Date Pros + Cons
Con Can only "redact" a posted message but neither "delete" nor "edit" it
The ability to edit a posted message is a powerful feature that has come to be expected since the rise of social media. Several other major chat platforms include this feature. Matrix.org's protocols enable you to "redact" a message (mark it as redacted whereas it is removed from view), but not truly delete or edit it. Deletion and editing are in the works, but in the meantime... CON.
Con End-to-end encryption is in beta
E2E beta landed in Nov 2016 with the most popular Matrix client having already implemented E2E. It should be out of beta by February-March 2017. The big remaining limitations are: 1. bad UX when verifying devices, 2. inability to share E2E history to new devices, 3. various annoying bugs where E2E messages aren't decryptable, but these are almost all fixed now.