With Hangouts Chat, you can communicate with teams and people in rooms—messages are organized into different topics, so you can hold multiple conversations at the same time.
Here are some key differences:
Same as classic Hangouts chat, plus advanced notification preferences to follow relevant conversations
Notifications for messages, contacts, and sounds
Currently, you can only invite people or groups in your organization to a room in Chat.
Yes. Direct messages that you receive in classic Hangouts are synchronized with Chat. Currently, group conversations and rooms in Chat aren’t synced with classic Hangouts.
Currently, there’s no way to delete a room. You can leave a room to hide it in your room list. If you created the room, you can ask all members to leave the room to effectively delete it for everyone. For more information on rooms, see Get started with Hangouts Chat.