Nice work freemind guys. I use this software all the time, especially for taking notes in meetings. It has really changed the way I work.
I thought this survey might interest you:
It was a survey completed by users on mind maps. Interesting to note people wanted to export mind maps often and found this difficult. I know I've tried to use it for taking minutes in meetings but have but when I send out the export other users can have difficulty opening and understanding it.
Love you work, Simplicity and user friendly is definately the way to go.