Not only the iPad is hot, the same is true for mind map apps for the iPad. Right now there are almost twenty. Although all kinds of blogs mention top 5 lists of mind map apps, the majority is of inferior quality. To point out one major issue: most apps work only on the iPad. Mind maps made can not be exported or exchanged. That’s ok if you just make mind maps for fun, however for professional mind mappers this is a major drawback. For example using the pricy iMindmap mobile HD (€ 25.99) it is possible to export mind maps, but not import. If you want to work cross platform, both functions are crucial. For bulky mind maps it’s still more comfortable to fine tune them on a computer. Being ‘on the road’ it’s easier using the iPad. In a reaction to a blog in october, an employee of ThinkBuzan states that “I am pleased to say that our team is currently advancing the app’s import feature so that it will allow you import mind maps created on iMindMap desktop onto your iPad”. It’s still not possible. A lot of apps even don’t have an email function. So to no surprise iThoughts HD tops the list. It’s flexible and has a lot of import and export functions. But the ultimate iPad mind map app has yet to be developed. Compatibility, exchangeability, flexibility and various import/export functions, that’s what professional user want. Who is picking up the glove?
View hans buskes's profile
mastermindmaps 
Something else to look out for when choosing a mindmapping app is whether you have to buy it twice in order to get a great experience on all your iOS devices (iPad, iPhone, iPod touch). As iBlueSky is a universal app (as of version 3.0), you only have to buy it once and existing users get the upgraded iPad version for free.
Mind maps made on the iMindMap can be exported by email (I do this all the time) as IMM file, an image and PDF. If you use the IMM format and you have iMindMap your desk top you can then edit, tweak etc you mindmap produced on your ipad. However you cannot yet import to the iPad (however I am sure that this will happen). As far as I understand from the developers allowing export and import is restricted by Apple and the size of memory/processing power. The totally awesome thing about the iPad version is the ability to present a map direct to a projector.iMindmap on the iPad and on the desktop is amazing, intuitive and very easy to use.
iThoughts is by all accounts: professional reviews and trusted friends, an excellent application but a virtual keyboard compared to writing your text. In my experience if it’s mobile mind mapping you want, I would recommend running MindManager in Ink mode on a Windows 7 Tablet PC (MindManager has had ink in the application since version 6, prior to that it was extra called X5 Tablet). Unfortunately there is a drawback, it will cost a lot more than iPad and a iThoughts HD. Tip: buy a Tablet PC on eBay they can be cheaper than an iPad and have much more functionality. I have been doing this since 2005. If the iPad, ran Flash then I could access Mindjet Catalyst via a browser (not ink enabled). Not sure how iMindMap 5 online will behave or not on the iPad.