NotebookLM vs Obsidian: Source Research or a Notes Vault?

Priya has until November 10, 2026 to brief her director on state-level broadband subsidies. She has 38 sources: agency reports, two audits, a legislative summary and a recorded hearing on YouTube. She will not need most of them after the briefing.

Recommendation: Gemini Notebook, on the free tier. One notebook holds all 38 sources (the free limit is 50), and she can ask "which reports disagree on the cost per household?" and click each citation to the passage. The audio overview gives her something to listen to on the commute. Obsidian would make her read and summarize every report by hand first. When the briefing is done, she should save the five answers she relied on as notes and export them to Google Docs, because the notebook is not where she keeps work long term.

Daniel has kept engineering notes since 2020: incident write-ups, design decisions, commands he always forgets. There are about 2,400 Markdown files, and his employer's policy forbids uploading internal documents to consumer AI tools.

Recommendation: Obsidian. His notes are already Markdown, so the vault is just a folder he points the app at. Backlinks show every incident that mentions a given service, and nothing leaves the machine unless he turns on Sync. If he wants AI later, a community plugin can run a local model over the vault. Gemini Notebook is the wrong tool here twice: it would mean uploading internal documents to Google, and 2,400 files would need dozens of notebooks of 50 sources each, with no way to ask a question across them.

Ama is a second-year internal medicine resident with boards in June 2027. She has 45 guideline PDFs and review articles, plus three years of her own Obsidian notes from rotations: patterns she noticed, mistakes she made, mnemonics that worked.

Recommendation: both, with a clear split. The guidelines go into a Gemini Notebook, where she asks questions and generates study guides with citations to the source text. Her own notes stay in Obsidian, where she links each condition to the cases she saw. Once a week she exports a few Obsidian notes as Markdown and adds them as sources so the notebook can quiz her on her own material too. The rule that keeps it clean: anything she wrote lives in Obsidian first.

Tomás is drafting the second book of a fantasy trilogy. He has 600 notes on characters, places, timelines and a made-up language, and he writes on trains between Lisbon and Porto where the signal drops for an hour.

Recommendation: Obsidian. Every character note links to the places and events it touches, and the backlinks panel shows every scene where a minor character has appeared, which is how he catches continuity errors. The files sit on his laptop, so the train does not matter. Gemini Notebook could answer questions about his drafts if he uploaded them, but his world is mostly his own short notes, not long sources, and he would be rebuilding the links he already has.

Hana runs operations reviews for small manufacturers. Her notes are her own: interview notes, site-visit observations, recommendations she made last year. She tried Gemini Notebook, but uploading notes one by one into separate notebooks did not feel like a notes app. She tried Obsidian, and gave up on configuring an AI plugin.

Recommendation: a hosted Markdown notes app with AI chat, such as Scribelet. She writes notes, links them with wikilinks, and asks "what did I recommend to the Leeds plant about changeovers?" to get an answer with citations to the notes. It imports her trial Obsidian vault. The trade-off is that notes are hosted (encrypted at rest) rather than local files, and it is web and iOS only for now.