Anyone using a 3D Mouse?

I've been looking at getting a 3D mouse, to assist in dealing with the problems I have in navigating within Blender and other environments. In particular I'm looking at SpaceNavigator:
http://www.3dconnexion.com/solutions/blender.php
Since their starter (PE) model does not cost much more than the mouse I tend to use (MX310) I figured it would be a reasonable investment. Does anyone have experience in using these things, either in working in Blender or other apps? I can't find one that's 'out of the box' over at MicroCenter so I can't test-drive the thing.
[Admittedly I'm also looking at this from a discount perspective - LL is working with Logitech to bundle in a free, reasonable-quality headset as their upcoming Viewer will work natively with the SpaceNav. And as someone who's gone through 6 headsets in 3 years, I'm always looking for spares.
]
--TSK
http://www.3dconnexion.com/solutions/blender.php
Since their starter (PE) model does not cost much more than the mouse I tend to use (MX310) I figured it would be a reasonable investment. Does anyone have experience in using these things, either in working in Blender or other apps? I can't find one that's 'out of the box' over at MicroCenter so I can't test-drive the thing.
[Admittedly I'm also looking at this from a discount perspective - LL is working with Logitech to bundle in a free, reasonable-quality headset as their upcoming Viewer will work natively with the SpaceNav. And as someone who's gone through 6 headsets in 3 years, I'm always looking for spares.

--TSK