Notion shines as a collaborative workspace with databases, kanban boards, calendars, and wikis in one place. Its AI features (auto-summarize, auto-fill properties, Q&A on your workspace) have matured significantly in 2026. Best for: teams that need structured, shared documentation.
Weaknesses: Offline mode is limited. Export is proprietary. Performance degrades with very large workspaces.
Obsidian's local-first, plain Markdown approach gives you full ownership of your data. The graph view reveals connections you didn't know existed. The plugin ecosystem (2000+ plugins) lets you build exactly the tool you need. Best for: individual researchers, writers, and deep thinkers.
Weaknesses: No built-in collaboration. Steep learning curve. Sync between devices requires setup.
Teams → Notion. Individuals building a lifelong knowledge base → Obsidian. Many knowledge workers use both: Notion for team docs, Obsidian for personal thinking.