When comparing Reach vs Matrix, the Slant community recommends Matrix for most people. In the question“What are the best group chat services?” Matrix is ranked 2nd while Reach is ranked 13th. The most important reason people chose Matrix is:
Matrix is an open standard, defining simple HTTP APIs so that devs can easily write their own clients, bots, bridges or servers. You're not locked into a specific set of implementations.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Mass message multiple people at once
Ability to send a single message to multiple people without exposing their contact information to each other. Reach sends individual messages to the group rather than starts a group chat.
Pro Personalized and Individual conversations in "Group Mode"
When sending a message to a group of people, Reach starts a private conversation in your Messages, Mail or WhatsApp apps respectively for each recipient
Pro Reusable Recipient Groups
Improve workflow productivity by creating reusable recipient groups
Pro All platforms in one: iMessage, Text/SMS, E-mail, WhatsApp, and Google Voice
Reach does not require the recipient to have Reach installed on their device. Instead it uses the existing messaging apps on the device to send the message to the recipient.
Pro Message Templates Feature
Prepare message templates which can be reused. Message templates can have recipients name variable, for example the template "hey {first name}!" will be populated with the recipients first name when the message is sent out
Pro Free texting through Google Voice
Reach integrates with Google Voice and allows to send free text messages in the U.S.A and low rates across the globe
Pro Fully automated mass texting with free SMS
Using Google Voice integration, Reach is able to send mass texts in a fully automated mode (without the need to press "Send" button for each message)
Pro Built on an open standard
Matrix is an open standard, defining simple HTTP APIs so that devs can easily write their own clients, bots, bridges or servers. You're not locked into a specific set of implementations.
Pro Bridges other networks into a single decentralised network
Matrix has bridges to IRC (freenode, moznet, oftc, snoonet etc), Slack, Gitter, Rocket.Chat, XMPP, SMS, SIP and others. The point is to 'matrix' all the different networks out there into one single decentralised network.
Pro Has an easy to use client called Riot
Riot.im is the easiest way to use Matrix, with great clients for Web, iOS and Android (and Fdroid).
Pro Does not require a centralized server to establish a connection between two users
Matrix is decentralized, there's no one central point that the information goes through and so no once central point of failure or control.
Pro Matrix prioritizes direct messaging with people the same as Slack-style groups
Matrix aims to "provide an analogous ecosystem to email - one where you can communicate with pretty much anyone, without caring what app or server they are using" using a neutral identity system.
Pro Supports different kinds of communication
Matrix is designed to support Instant Messaging, VoIP/WebRTC signalling (voice and video) and Internet of Things communication.
Pro Has an app store for 3rd party integrations & bots
Riot.im includes an app store with integrations for Github, JIRA, Jenkins, Giphy etc - and anyone can add more via Matrix.
Pro Offers choice of clients
Which can be found here.
Pro Maintains full conversation history
Pro Has an active community behind it
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
Con Need to press "Send" button per each recipient
When sending a message to a group, the user must press "Send" button for each recipient. The only work around is to use Google Voice integration for fully automatic mass texting
Con Keys cannot be checked automatically
You cannot automatically check keys of your recipients. Only manually.