I think SimpleMind is better than OpenMind because it’s a cooler app.
It looks nicer, with a simpler interface and smooth performance.
It’s easy to use, besides the possible lack of functionality.
It feels better to use because it’s a native OS X app, instead of a clumsy Java port.
It has all the features I need to map simple ideas and structures.
I’m using the free version, which can only export to PDF using the print function.