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 ClickUp or Bitrix24?
ClickUp also has more communication features, such as mentions, polls, groups/channels, and GIFs/emojis, as well as online document editing and document viewer. Bitrix24 has more CRM-related search options and a newsfeed, as well as a calendar and "Do not disturb" mode. Both competitors offer training and help resources, mobile/web/desktop apps, integrations, and SAML/SSO authentication, but Bitrix24 also offers end-to-end encryption and data/user import options.