I find the FK1000P to be superior in the functional sense but the appearance diff is gonna be personal preference.
While both products do best for me layered, when you're only doing one coat the FK1000P is mighty impressive. To be fair, I should point out that I get inconsistent durability from 845; sometimes it's simply amazing and other times it needs redone frequently...never did figure out why. No such issues with the FK1000P.
The best thing IME is the way it sheds dirt and protects against etching/etc. I've gotten to where I neglect the Yukon something awful because it always washes clean with zero issues, and I've left bugs on it for weeks; any of my other LSPs would be not only dead by now, but would have also allowed the long-standing contamination to do serious damage. This aspect of the Fk1000P has really impressed me. SuperBee364 had raved about this, and it was a big part of why I decided to try the stuff.
While 845 is "bright, reflective" and kinda "sealant-like", the FK1000P really does look like a thin layer of oh-so-shiny additional clear. Hard for me to verbalize how it strikes me, but I keep thinking that I shouldn't like it as much as I do on the Yukon's Carbon Metallic...like I oughta want to top it, but I actually like how it looks (and I'm really an old-school paste wax-look guy). Really the sort of thing you'd have to try for yourself I guess, but I don't think I'd choose it for a nonmetallic dark color. Hey, if you don't like how it looks it'll still be great for wheels. It doesn't look like Zaino. It doesn't look like KSG, UPP, BF or anything else I've ever used.