In motion satellite is a personal choice but I doubt there are many people that jump in an RV and travel cross country watching TV. If its just the wife and me traveling we don't often even turn on the radio, let alone the TV. In motion for us would be a waste of money because on short trips there isn't enough time to watch a movie and on long trips she likes to sit up front and keep an eye on my driving.
I have 2 Tailgaters. One permanent mount on the roof and one portable and have never been anywhere where we couldn't get signal.