I think that you should say nuts to them all. When you breakdown on the highway, you can then fend for yourself. You could keep a list of repair facilities that you have thoroughly researched in your vehicle and call them. Just like any of these services would do. Nobody is forcing you to go with Coach-Net or Good Sam. Personally I prefer to call a roadside service and have them take care of it.
I do have a dog in this fight though. Coachnet picked my 40' MH up from the side of the road in Canada in the middle of nowhere. They brought me to a repair facility. The repair facility determined that they couldn't fix it so Coachnet hauled us another 100 miles to the next one.
Not a penny out of pocket for 180 miles on a lowboy trailer. They have my membership until I stop driving an RV.