Using a Spacetec or 3Dconnexion device like that is a bit like using a TrackPoint that responds in all six degrees of freedom as opposed to only two, in terms of feel. There's a little movement, but not much.
Because of that, I wouldn't want to use it as a traditional mouse. However, it would make a great keyboard supplement/alternative for the intended 3D modeling purpose, or even for gaming. (Seriously, try out Descent or some other 6DoF game with it. Works quite well.)