I tried the $30 Inspiration/Palm version (free 1 month trial -- pretty good!), and I synchronized it with the desktop on Windows. The synchronization is a bit awkward, but not too bad. There's a menu item in Inspiration that lets you open the PalmOS Data file (.ihf). Then you save it to your desktop data folder (.isf). If you'd like you can export it back to the Palm (save as .isf). I had to read the manual to figure out how to get started; it's not very intuitive but really the PalmOS doesn't make this easy .
On Windows the PalmOS data files are saved in a rather unusual spot. Depending on how you browse to it you see two different paths, so I assume it's some virtual directory:
C:\Documents and Settings\All Users\Documents\Inspiration Handhelds\jfaughnanI'd never messed with this "shared documents" folder before, but it's evidently there for a reason.
C:\Documents and Settings\All Users\Shared Documents\Inspiration Handhelds\jfaughnan
So making the sync work takes some discipline. It's not like 'Desktop To Go' that theoretically keeps the desktop Word document and the Palm document automatically synchronized. I'd prefer something that didn't require thought, but given the limitations of Windows this is probably as good as one can do. (I didn't try this on my Mac because I still sync my CLIE to the PC - my wife tend to hog the Mac.)
Inspiration/Palm works surprisingly well on the CLIE's relatively high res screen. The images are crisp and I can get quite a bit on there. The Outliner is very simple to use. I like the graphical view better than I'd expected.
Inspiration doesn't have the glitzy output of MindManager (though I'm not sure MM does much more than Inspiration), and it's not nearly as powerful an Outliner as OmniOutliner, but this mega-cross-platform stuff is pretty interesting. I hope they are able to make the jump to Intel, but frankly the app is very speedy and would probably run ok with Rosetta. I'm going to be using it for a while and I expect I'll buy the Palm version.
 The Palm software was built for Windows 95, it was never redone to adjust to NT/2K/XP's multi-user model. This causes no end of problems, including making this sort of thing hard to do.