Hi Will, the Space Navigator model is really quite compact, it's got a 3 inch diameter circular base.

It actually only has 2 buttons on it, but it has the same kind of twisty knob thing as the higher end models.

Since it is so inexpensive, if you are interested in trying them out it might make sense to get this one first to see if you like that navigation method.

For the models with extra buttons, you can set up the buttons to generate different keyboard shortcuts, I don't think they really do anything else special like change the navigation or anything like that.

- Michael

Hi, yes, I'd be replacing my N52 so I'm looking at either the SpaceTraveler or Space Explorer - pricey (amazon has somewhat better prices) but I can't see myself not having programmable buttons for my apps!

Problem is, it's like have a mouse with a mouse wheel and then going to a machine without one - you become dependent on your button programs! Well at least the Traveler is supposed to be simple to take with you!

-Will