After some good and detailed comparisons by @bdavid we are moving ahead with testing our current favorite MindMeister.
Here are two examples of Mindmeister mindmaps
Mindmap about Spotify vs. Youtube Music - #7 by moritz
Mindmap with the content of Q2 2023 Spotify Earnings - #9 by moritz
Initial testing showed that there are some bugs with the version history function which does not work.
Additionally, there have been problems when trying to open the mindmaps on mobile web browsers.
We therefore highly recommend the well-made Mindmeister mobile app.
A list of general Mindmaping principles will be created at Guideline:Mindmap principles - InvestmentWiki
Please share any thoughts, criticisms, problems, questions or other tool suggestions.