When comparing Freemind vs Momentum, the Slant community recommends Freemind for most people. In the question“What are the best cross-platform productivity tools?” Freemind is ranked 6th while Momentum is ranked 8th.
Ranked in these QuestionsQuestion Ranking
Pro Free and open source
Pro Intuitive UI with drag and drop support
For the most part, navigating the editor is pretty intuitive - moving around is done by clicking and dragging the background, clicking on nodes will expand/collapse them, dragging and dropping in files will add them, etc. It also offers shortcuts for power users. For example, ctrl + up/down will rearrange ideas up/down, alt +up/down will zoom in/out, etc.
Pro Lots of export options, including html with folding
Freemind offers many choices when exporting. It allows exporting the project as Java Applet, Flash file, Open Office Writer document, picture (png, jpg), PDF, SVG, multiple variants of (x)html, among other options.
Pro Good documentation
Pro Cross-platform desktop and mobile
Works on Windows, OS X, Linux, iOS and Android.
Pro Fullscreen mode available with a patch
A user-contributed patch is available that adds fullscreen mode to FreeMind.
Pro Can copy entire hierarchy to/from Word with a simple copy/paste action
Freemind allows quickly copying over structure of the mindmap as a bulleted, tab-indented list starting at the node selected. It can also take a bulleted, tab-indented list and create a mindmap from it.
Pro Multi-user support
Pro Supports media files, recognizes URLs and commands
Freemind accepts drag-and-drop for any kind of file, URL or command as part of the mindmap. Files it recognizes, like images, will be displayed. Other files will open in a separate, appropriate application. URLs, links to folders, and executable commands pasted in will be recognized and turned in to clickable links.
Pro Supports node and map encryption
Pro Revision control
Pro Automated Next Steps
Next steps have a separate view. Tasks can be updated sequentially or parallel.
Pro Projects and Tasks can be endlessly nested
You can nest multiple projects with tasks, there is no limit.
Pro Has an offline mode
No permanent internet connection needed.
Pro Clean design
Lots of space helps focus on the tasks.
Pro Specifically designed for GTD
Web-based, progressive-web-app (PWA).
Pro Realtime synch
Data instantly updates on all devices.
Con Boring visual appearance
Con Beta interface is confusing for first-timers
The interface is very opinionated (this is a good thing). But it is not obvious how to map user's own GTD variant onto the one the author has in mind. Maybe after it is in production, there will be better on-boarding.