1. Notion — the workspace giant
What it is: An all-in-one workspace: docs, databases, wikis, projects. The most capable general-purpose knowledge app in the lineup, especially for teams.
Genuine strengths: The database model is excellent. Team wikis, project trackers and personal note systems all fit inside one app. Huge template ecosystem. Notion AI is genuinely useful inside Notion pages.
Best for: Teams and individuals who want one workspace for docs, projects and notes, and who don’t need their AI assistants outside Notion to see the content.
Pricing: Free personal plan; paid team tiers from around $10/user/mo. Notion AI is a separate add-on.
Deeper head-to-head: BrainTube vs Notion.
2. Obsidian — local-first Markdown, yours forever
What it is: A Markdown editor over your own file system, with a graph view, backlinks and a vast plugin ecosystem.
Genuine strengths: Every note is a plain .md file on your disk — the strongest data ownership story in the category. Plugin community is one of the most active anywhere. Graph view and backlinks are still best-in-class for people who genuinely tend a vault.
Best for: Long-lived personal notes you enjoy maintaining, and anyone whose non-negotiable is “the files are mine, on my disk, forever.”
Pricing: Free for personal use. Sync $4/mo, Publish $8/mo as optional add-ons.
Deeper head-to-head: BrainTube vs Obsidian.
3. BrainTube — persistent memory for every AI you use
What it is: BrainTube compiles what you watch and read — YouTube videos, podcasts, articles, PDFs — into a knowledge base that every AI can query. Chrome extension for one-click capture, automatic transcription, a Postgres knowledge graph, FSRS-5 spaced repetition for what you want to remember, and a native MCP server that plugs into Claude.ai, Claude Desktop, ChatGPT (via MCP connectors), Cursor and other MCP-compatible clients. Full JSON export on every plan including Free.
Genuine strengths: Auto-capture with real transcripts, cited-to-source recall down to the exact timestamp in a video, and the same corpus queryable from whichever AI is best this quarter — including ones that don’t exist yet.
Best for: People whose knowledge mostly comes in as long-form video, podcasts and articles, and who want that library usable from every AI tool they already touch. Positioning: save once, query anywhere.
Pricing: Free $0 (30 credits/mo) · Starter $9 (250) · Pro $19 (1,000) · Pro+ $49 (5,000).
Honest limits: Younger product than Notion, Obsidian, Recall or Readwise; smaller community and plugin surface. In-app reading UX is functional but less polished than Recall’s. If your day already runs inside Notion or an Obsidian vault, keep it — BrainTube is a memory layer for AI, not a workspace replacement.
4. Mem — the AI-native notes app
What it is: A notes app built around an assistant that helps organise and resurface what you write.
Genuine strengths: Very low-friction capture inside the app, automatic tagging and connections, a mature in-app assistant.
Best for: People who write a lot of short-form notes and want automatic organisation without folders or manual tagging.
Pricing: Around $10/mo (Mem+ tier).
5. Recall — save-and-chat for articles, videos and podcasts
What it is: A capture-and-chat app for articles, YouTube, podcasts and PDFs, with strong in-app summarization.
Genuine strengths: Polished capture UX, good in-app summaries, native handling of media alongside articles.
Best for: People who want a single, self-contained “save and ask” app and are happy to chat with their content inside Recall itself.
Pricing: Free tier; premium roughly $7–10/mo.
Deeper head-to-head: BrainTube vs Recall.
6. Capacities — object-based notes
What it is: A note-taking app organised around typed objects (people, books, ideas, projects) rather than pages in folders.
Genuine strengths: The object model makes structured personal knowledge — reading logs, contact notes, project references — feel natural without setting up databases by hand.
Best for: People who like the idea of Notion databases but find building schemas exhausting, and prefer opinionated structure out of the box.
7. Tana — nodes, tags and supertags
What it is: An outliner where every node can be typed with a “supertag” and queried like a database row.
Genuine strengths: Extremely powerful once you internalise the model — a single outline can behave as CRM, project tracker, reading log and journal, all queryable together. Loved by power users.
Best for: Serious tool-tinkerers who enjoy shaping their own system and want the payoff of a fully queryable personal database.
8. Heptabase — visual thinking on a canvas
What it is: A whiteboard-first notes tool where cards sit on infinite canvases and get grouped, linked and arranged spatially.
Genuine strengths: Best-in-class for research where seeing the shape of your thinking matters — literature reviews, complex arguments, design work.
Best for: Researchers and visual thinkers who want to lay out ideas spatially, not linearly.
How to actually choose — a 3-question decision guide
1. Do you mostly write notes, or mostly want to query what you consumed? Writing-first: Obsidian, Notion, Tana, Capacities, Heptabase, Mem. Query-first: BrainTube, Recall, NotebookLM. Get this axis right and the rest is easy.
2. Does the tool capture what you actually consume without your intervention? If you have to hand-type every source, the tool will lose to your calendar. Auto-capture matters more than any other feature for people whose knowledge is in videos, podcasts and articles.
3. Can every AI you use read your knowledge — including the AI you’ll switch to in six months? Tools whose AI lives only inside their own app are fine today and a lock-in tomorrow. Tools that expose your corpus over an open protocol like MCP travel with you across AI clients.
A common 2026 shape is one writing tool (Obsidian or Notion) plus one memory-layer tool that captures media and exposes it to every AI (BrainTube). They solve different halves of the problem. For the deeper category critique, read what second brain apps get wrong.