I'm an AMA member and I have their roadside assistance. My parents do also. They've used the assistance twice or three times over the years. Once it was good, once it was very, very slow, and I can't recall for certain whether they've used it a third time or not.
I've only tried to use them once, and the same thing happened to me that happened to my parents on their bad experience: AMA's operator told me when to expect a service vehicle (an hour and a half to two hours later, though I was in a huge metropolis at the time). After the time had elapsed and the service or carrier vehicle should have arrived, the AMA called me back and said the service provider had cancelled, that a different company was being dispatched by AMA, and that it would be a couple more hours. Since that _exact_ story had been given when my parents had to wait about 4 hours for help several months before (also in a large city), I decided this was a pattern rather than a coincidence. I called someone else for help, stowed the bike at a nearby business temporarily, went and rented a U-haul trailer, and hauled the bike home.
I'm still an AMA member, but I don't have a lot of confidence in their roadside assistance program. Hopefully I'll never _really_ need it.