Any polish or cleaner without fillers or oils will work fine, and there's a ton of them out there. Some people will make excuses to defend the Zaino line or glorify it until they're blue in the face. I just call them fanboys, add them to the ignore list, and move along.
I used the stuff for over a year. Yes, Zaino makes good products. No, I never saw one that was hands-down better than the main competition. I've since abandoned the whole line since I saw no reason to use it anymore if I didn't like the look provided or the process. I go over the car enough to not care about durability, and if I did, I'd probably be using SG anyway.
And the fact of the matter is that the advertising and instructions do nothing but mislead the customer base (meaning, 99% of the people that end up buying the stuff) that don't know the first thing about proper prep or detailing in general. The fact that there's a ton of zealots spread across every automotive forum you can name that think it's the only good stuff on the market proves this. Any real detailer will tell you that process matters 10x more than the product used and won't make excuses to glorify any single line made.
I plan on buying the Z-PC to judge it for myself, just as I have the rest of the Zaino line. I expect it to be something along the lines of FPII, an extremely mild polish with no fillers to leave a glossy surface ready for an LSP. I highly doubt it'll be superior to comparable offerings from Poorboys, Menzerna, Meguiar's, Optimum, 3M, or any other product we're all used to seeing, but I AM convinced that it will be a quality offering that I'll find a use for.
As Autopians, keeping an open mind is key. People that glorify a certain line are doing the EXACT opposite. No matter who you are, you can't deny that Zaino's marketing descriptions are both misleading and brew a whole bunch of ignorance from people that don't know any better. They are not focused towards "exotic" or rare paint jobs. You're only kidding yourself if you think so.