"The main difference between them is response time and the availability of a tech to answer questions."
Response time is in no way to judge a towing service. Response time depends a lot on wrecker availability and distance from you.
A better judge of service is the equipment they use. There is a huge difference between towing a 32 ft gasser and a 40 ft pusher. The only way to get this info is to question those that have been towed.
I have been towed through Coach Net and in talking to the tow driver, he said that they have contracts with several insurance companies.
BTW, FMCA did not drop CoachNet, it was the other way around. CN decided they could make more $$ by siding with Good Sam