Viber vs Flock

Viber has native apps for both Windows and Mac that allow you to send and receive messages from your desktop. You can also use the desktop to make and receive calls. Synchronizes between all devices you are using Viber on. Allows transferring calls between devices.

Viber has really well implemented voice tech. It has comparable quality to Skype and you can even tranfer calls from your phone to your desktop seamlessly.

Viber uses data connection and the app is free.

The interface is simple, functional and intuitive.

Viber is tied to your phone number so it can quickly see who else in your contacts list is using the application.

Viber includes Android Wear support on Android 4.3 or higher and Viber 5.3 or higher.

Viber's protocol uses the same concepts of the "double ratchet" protocol used in Open Whisper Systems Signal application.

It's possible to be a fly on the wall on other group or one-to-one chats that have been opened up to the public. These public chats are often promotional chats with celebrities.

Can call friends using voice or video options.

This has an advantage in that if you text someone who uses Viber it will be free, if not it will just revert to SMS. This means you can replace your standard messaging app with Viber as well.

Starting with Viber 6.0 the encryption keys are stored only on the clients themselves, not even Viber itself has access to them.

One of the best things about Viber is how it handles setup and sending messages. Viber uses your existing number as your ID, so you don't need to create a separate Viber account.

Viber allows creating groups of up to 200 people on the Android version of Viber. It also has a cool "smart notifications" feature to prevent being overwhelmed with notifications if a lot of people are active in a chat group.

Viber has made a documentation available, explaining in great details their encryption system and giving good insight on how it works.

They have apps for Windows, Mac, Chrome, iOS, Android and web interface. And all the chat sessions are always on sync.

It is half the price of Slack and full of nice features like polls, assign to do's, etc.

Unlike its rivals, it not only allows you to receive events, but also allows you to push content to it and receive various user action events.

Moving a team or organization to flock does not require any setup from the company's IT team. At max, what might be required would be to whitelist their domain in case the organization's IT team has gotten external domains blocked. You can simply download Flock and invite others in your organization by using their email ids in order to start collaborating. That's all there is in the name of setup.

Most of its features are free, even video conferences. But also they have a Pro version with unlimited chat history, Active Directory integration among other things.

There is no limit on the number of groups or of group members. Similarly, within a team you can have unlimited members. There is no limit of number of teams too.

Flock is offering an app that is faster than Slack.

For every team, the permissions and restrictions can easily be set over the participating members and the conversations they are having.

Posting messages is more fun with them in addition to emojis.

There are multiple options like slash commands, message buttons, chat buttons, attachment picker etc., where the integrations can surface inside the native app. This greatly eases the discoverability of a integration, making it really easy for the team members to find and use the integrations.