Reviewers largely see Slack as the default hub for team communication: fast, reliable, and especially strong at channel-based organization, threads, search, file sharing, huddles, and integrations that reduce email and keep work moving. Many say it works particularly well for remote teams, startups, and engineering workflows. The main complaint is noise: too many channels, threads, and notifications can bury important messages, especially across multiple workspaces. Some also mention a learning curve, feature clutter, uneven video or mobile performance, and limits or cost concerns on the free and paid plans.