I have it, and hope I never have to use it. What changed my mind was recent trouble I had with the vehicle at the time and seeing a picture of a truck and trailer with horse in it at the Horse Park of NJ. I frequently show on my own...bought in hook, line and sinker.
I've used it too, but never when I've had the trailer with me. It is just so reassuring when they answer the phone and ask: "Are you and your horses alright? Do you need medical or veterinary assistance?"
I must be the only person on the planet that actually cancelled USRider...:-( Had it for a couple of years and both times I really needed them they were not really helpful. Oh well, glad it worked out for the rest of you.