ConceptDraw MINDMAP: mindmapping and brainstorming tool overviewMindManager is definitely the market leader (alas, Inspiration, you peaked too early -- though I do hope you hang in there) in this segment. It's a fairly expensive product however, and it's very much a "lock-in" play. You put your data in MindManager, you'll never get it out again.
.. MindManager Import You can seamlessly open files created by MindManager users on both Windows and Mac OS...
Until now. MINDMAP looks like it's aiming for the MindManager market, and it supports OPML export. They need to drop the price though if they want to get serious -- MindManager 7 for Mac is $130! There's no way MINDMAP can charge $70 more than MindManager and be a serious alternative.
I suggest they think about charging $130 for a dual platform license -- for the same price as MM get the right to use both the Windows and OS X versions on all machines one uses.