Obsidian

Pros

• Local storage using plaintext markdown files ensures full user ownership and data longevity.
• Powerful internal linking and search capabilities, allowing for a Wikipedia-style personal knowledge base.
• Extremely flexible and customizable, including support for Vim keybindings and advanced data structuring.
• Fast performance and quick page loading compared to cloud-dependent competitors.

Cons

• Official cross-platform sync is a paid service, which some users find restrictive.
• Steep learning curve; the interface and configuration options can be overwhelming for new users.
• Mobile application is generally viewed as less capable than the desktop version.
• Weak mobile widget support and lack of certain organizational features like alphabetical list anchoring.

Caveats

• While official sync is paid, users often utilize free alternatives like iCloud or manual file transfers, though these may require more technical setup.
• The high level of customization can lead to 'fiddling' with the tool more than actually using it for productivity.

Best for

• Users who prioritize data privacy and local file control.
• Power users and developers who want a highly extensible, markdown-centric environment.
• Building complex, interconnected knowledge bases or 'second brains'.

Avoid if

• You want a simple, 'out-of-the-box' experience without a learning curve.
• You require a free, seamless official sync service across all devices.
• You rely heavily on mobile widgets for quick note access.