Been playing with the SpaceNavigator now for a few days and here are my preliminary conclusions which I choose to share so that others can make a more informed purchasing decision.
When it comes to usefulness in connection with C4D, its:
(A) A fairly decent user experience on Windows - worth purchasing.
(B) Awful user experience on the Mac - Do NOT purchase!
I’m on a mac and to find out how the SpaceNavigator performed inside C4D on Windows, I booted up to windows on the same machine via BootCamp. The fluid motion control and scene navigation compared to OS X was shockingly good by comparison. Nothing close to the jerky, staggered motion experience on the Mac side. However, this is probably due to better OpenGL performance on Windows compared to OS X.
While still booted up inside Windows, I took the opportunity to fire up Rhino. I was completely blown away by how well the Space Navigator performed inside Rhino. If scene navigation inside C4D (Windows) with the SpaceNavigator was decent, it was silky smooth and easy to use inside Rhino. Absolute fantastic 3D user experience.
I’m seriously considering using C4D on Windows now more than on the Mac. The fluidity and OpenGL performance in conjunction with the SpaceNavigator warrants the better user 3D-experience. I was surprised how terrible the SpaceNavigator functionality is in conjunction with Adobe PhotoShop / Adobe apps. It’s pretty much useless because the slightest hand movements cause unpredictable results and basically the only thing you can realistically do with the Space Navigator in PhotoShop is zoom in or out of a document, something the scroll- wheel on your mouse does better(!) Another bummer is that the lack of Zbrush support which is a disappointment considering how useful that would be.
Anyway, long story short: The SpaceNavigator is pretty good on Windows and a total paper weight on OS X.
Cheers / Alex