I'd sooner do ONR than completely waterless. I think a fair test would be to have three cars that were fully corrected, then subject to the same dirt. Car 1 is washed the detailer's way, car 2 is washed using ONR and car 3 using the above system. Repeat several times (5, 10, 20) and after each set, analyse the paintwork to see which inflicted the most damage.