we sell that stuff to mechanics that work on diesel forklifts, top-loaders and other heavy machinery, and they swear by it. I've used it to clean all kinds of messes and it cuts through grease and oil that nothing else will budge. One thing I've noticed is that if you have some heavier crud to clean, spray it on and let it work for a couple minutes, and it'll eat into it more. Good stuff in my opinion.
All the trucks in our fleet are white (wtf) and sometimes Oil Eaters is the only thing that will get the occasional oily handprint off. Especially the older trucks that have gone chalky. Glad to hear it's working for ya.