For Windows users who prefer native apps and control over their data, Connected Text (paid, closed source ultimate kitchen sink with 30 days trial)[1] and WikiPad (free, open-source wiki engine)[2] are good alternatives to Roam.

Personally, I use TreeSheets [3] for note-taking and try to organize them as nodes in yEd [4] when I want to gain insight, but that quickly grows out of control and becomes unmanageable. Auto-linking and graph overview are extremely powerful features in this regard, but my gripe with e.g. Roam's approach (judging by screenshots) is that you can't visually filter out all the nodes at ones and "walk" the paths in a filtered graph -- that's why I consider switching from yEd to VUE [5], which has more decent filtering/search/layering/grouping options.

In general, [6] and [7] have good coverage of existing note-taking and mind-mapping tools.

Does Roam have any data export options though? If so, I might give it a try.

[1]: http://www.connectedtext.com/

[2]: http://wikidpad.sourceforge.net/

[3]: http://strlen.com/treesheets/

[4]: https://www.yworks.com/products/yed

[5]: http://vue.tufts.edu/index.cfm

[6]: https://pauljmiller.wordpress.com/category/software/note-tak...

[7]: https://pauljmiller.wordpress.com/category/software/mind-map...