Hi and welcome to the forum.
I think Good Sam membership is a no brainer if you're going to be doing any amount of travel to speak of, because of the 10% discount at CG's.
For road service, however, you might want to use the search feature here to research this topic. IMO, a good majority of members here with DP's favor Coach Net over GS road service largely due to the 24x7 technical support and their expertise in managing any sort of road side emergency... including finding and dispatching a tow service capable of handling a big rig properly. Note I indicated "properly".