Who has best Roadside Assistance Program?

Good Sam and Coach-Net seem to be the most popular.
Some use AAA and, some will tell you to check with your insurance company, they may have the service available.
You will find pros and cons to each service. I don't think you will find a 'best' Program.

Good Sam has been good for me so far.

Good Sam has served me well so far. I have 4 service calls in the past 24 month all without a hitch.
AAA service is great in some ares and bad in others. It is an association made up of various clubs.
FMCA also seems to have a quality product.
You have another choice and that is your RV insurance policy might cover towing and breakdown.
Whichever way you go MAKE SURE TO READ THE COVERAGE terms and conditions.
That seems to be the biggest problem with the policies no one reads and assumes they are covered.
For example FMCA coverage states;
Winch-out Service

Benefits apply as long as the RV can be safely reached from an established, maintained road, thoroughfare, paved street, highway, public or private parking lot. Winch-out coverage applies when member is attending FMCA events and rallies.Winch-out services do NOT apply if the RV is more than 50 feet from an established, maintained road or thoroughfare, or was intentionally driven off the road, or when your RV cannot be reached safely. Benefit does not apply to recovery work (e.g., RV is down a hillside or embankment) or if the RV has been in an accident.
Good sam states;
Vehicles in a repair facility, off-road area*,sand beach area, or any unattended, unlicensed, or abandoned vehicles.

An off-road area is defined as an area OFF of any of the following: hard-packed or graded dirt public road, paved street, driveway, parking lot, highway, freeway, expressway or adjacent shoulder.
There are differences in these 2 statements

AAA NO INFO until after you purchase then you get to see contract.