A brilliant, powerful program - I'm amazed it's free and that it's not more well-known.
I definitely recommend checking it out. Vote it up if you like it - more people should know about it.

In order of what I find most outstanding:

• you can have nodes within nodes within nodes - making it easy to express a large amount of info in an ordered way. Also, you're not tied to a master node - you have an open space, like cmap.

• a node can appear in many places - change one, they all change

• a node can appear as a picture - just drag and drop and you've created one. (can also be a link...a list...and of course any node can have text, which can be seen quickly by mouse-over or opened for editing)

• outline view, tags

• you can draw different lines between nodes to show relationships

DRAWBACKS (major and minor):

• search is case-sensitive ONLY. this can be a big problem: you find yourself cutting the first letter off words to find them!
• i find the text input area pretty ugly and don't like editing text much in it...for many of my own uses, this is a killer
• nodes that do appear in multiple places: you can't delete all instances in one go
• if you open a backup copy of a project, you will find littered throughout your text "\n" in various places! And it would have lost its paragraphing
• you can't just drag and drop nodes into each other...you have to click and open them and then throw the node in....

Some of these problems may have been fixed in latest version.