I've had good service from Coach-Net over the years, and recently tried the service that Progressive Insurance provides, also with good results. When a previous Class A blew a rear wheel bearing, the tow operator had no problem hooking up from the rear and strapping the steering wheel down to tow it to the service shop.
Good Sam contracts out their roadside service plan, currently to Allstate Motor Club as I recall. Some of their previous contractors haven't been very well rated, but Allstate gets pretty good marks from the towing industry.