Reviewers describe TiddlyWiki as an unusually flexible, reliable personal knowledge tool they use every day for notes, journals, task lists, tutorials, project tracking, bookmarks, spaced repetition, and even custom apps. They repeatedly praise offline use, local ownership, long-term durability, single-file portability, and deep customization, with many saying it can grow from a simple notebook into something much more powerful. The main drawback mentioned is a steep learning curve, partly tied to documentation, though users say the community is friendly and helpful.