There is a 3rd alternative...
Atolia, the one and only workspace your team needs
Atolia is a power-packed all-in-one digital workplace: Chat, Video calls, Tasks & Projects, Calendars, Documents, Notes...
Accelerate your team's collaboration game.
Implement it in minutes and save money. Atolia is cheaper than most of the business instant messaging apps.
Why choose Lark or Rocket.Chat?
Lark's entry level price is $12/user/month, while Rocket.Chat has no entry level price. However, Rocket.Chat does offer a 30-day free trial, while Lark does not. Both platforms offer a free version and roles management, but Rocket.Chat has the advantage of custom domain name and workspace and user activity monitoring. Overall, Lark seems to have a stronger focus on document management and collaboration, with features such as online document editing, document viewer, and notes-taking. Rocket.Chat, on the other hand, offers more advanced video conferencing features such as breakout rooms and recording, but lacks some basic features such as screen sharing and audio call.