You can use auto care products at twice the price if you want. I always look for a less expensive way to do the same thing. Goes back to my childhood. My parents were savers and not spenders(depression kids).
Ken's comment about "Reliable" is valid. I have been using it to do the difficult cleaning jobs since he talked me into trying it and I agree that it is the best I have found.
What I was thinking of with the comment about using auto paint care products was in terms of one of the wash/wax products or the wax products. I don't have full body paint on the motorhome, but if I ever buy another new one it will have.