I have to think that the vast majority of RVers have ERS (Emergency Road Service) with the main ones being Coach-Net, Good Sam, Allstate, and AAA ...there may be others who offer RV coverage also but I think those are the main ones.
We have Coach-Net and are satisfied but haven't really needed them for anything crucial. A Coach-Net exclusive is their 24/7 Technical Assistance Hotline where you can call for advice about all problems you might encounter with your rig.
Some, however, claim that being "self-insured" when it comes to ERS is the way to go. In other words, paying out of pocket for any towing or other services needed and arranging for road service yourself. They claim that the money you save in ERS premiums year after year will more than pay for the occassional tow or lock out, etc. I suppose if you're lucky and have nothing go wrong, then self-insuring is something that can be considred.
However, most of us like the comfort of knowing we can call one number in case of an emergency mechanical breakdown and get some help especially in an area we might be unfamiliar with. Can you imagine the stress of having to find an on-call service provider for a tow or mechanical assist when you are in an unfamiliar area?
I think ERS is worth it for just that peace of mind whether it be Coach-Net, Good Sam or another service.
In places that are less populated, all the ERS services may use the same providers as it's not the ERS itself that comes out to you but rather they provide the service of looking up and sending an independent provider to assist you on the road.