I started messing with MindNode last night, doing some Marooned! brainstorming and planning; it was pretty useful, I think, and definitely works well when you're throwing down ideas as fast as possible without necessarily aiming them all in the same direction.
Here's the start of my Marooned! map in MindNode:
MindNode lets you export/import FreeMind files as well, so I grabbed it to compare. It's a Java app (ugh), but it's got a lot of additional features, and will auto-fit your items, automatically adjusting the map so nothing is overlapping. If MindNode does that, it's limited to the Pro version.
Here's the same map in FreeMind:
As much as I hate Java apps (non-native UI! klunky widgets! the horror!), I'm going to give FreeNode a fair shake. If actually using it feels fairly fluid and straight-forward, I'll go that direction. It's certainly got more features (attach icons to nodes, for example) beyond even what MindNode Pro offers.
Choosing a Java app over a similar native app is a big step for me. Maybe one day I'll overcome my Java prejudices in the name of productivity. Eclipse is the only other Java app I don't mind using…