Rig Shots vs. Sitting in other car panning

Is there a difference in having a rig set up shooting, and shooting in another car panning? I know the angles will be different but will I have the same results? I'm just wondering...

I would say you will get a much higher success rate with a rig if you want really slow shutter speeds, as you get thrown about a lot in a car. On the downside you need more equipment, there's much potential for an expensive accident, and you may have to get rid of the rig in post processing.