I have used both and they are both about the same. In 2013 Good Sam dispatched a service man to do a brake job on a Holiday Rambler diesel pusher that left me stranded in Orange Beach AL.
4 weeks ago, I had a blowout on an f250 pulling my FR 5vr. I was in the center lane of traffic on I10 west bound, on the up slope of the Biloxi River Bridge. Coachnet said that it would be about 2 hrs before a service truck could get there. They were welcomed when they arrived. $3500 worth of damage later we are about ready to camp again. So in my opinion, both are great.
My battery went dead with my keys in the ignition and the doors locked, in a very remote area while hunting. Neither Coachnet nor Goodsam could find anyone to come unlock door. Coachnet called the Sheriff of the county I was in and he unlocked it.
2014 Rockwood 8281WS
2011 F150 4x4, 5.0, 3.73 rear