Well ive been using espuma revolution for a year and its not damaged the finish on any of the cars I use it on. This just seemed to be a cheaper alternative, but Ive had mixed reviews on it over at DW, mainly bad ones about it being nothing more than an APC and not having the ability to clean heavily fucked wheels.
It needs to be as good or almost as good as espuma and cheaper lol. Smart wheels isnt far off the price of espuma even on ebay and doesnt seem to have the dilution ratio of espuma. I use espuma heavily diluted - 20:1 and it still works as well as I expect it to. Awsome product.
Problem is I have a mate who goes besserk when using it. uses almost half a spray bottle when doing his wheels ffs.