I have and use both. I think its a toss up. For non-detailing people, I always recommend 845 or 476s and don't mention FK1000P because of the trim-safeness and tight beading. Here's how I'd break it down:
476s:
- tighter, better beading
- single coat gives some of the best protection out there, better than a single coat of FK1000P by multiple weeks (for me)
- trim safe. Intentionally apply it to your trim and sleep easy.
FK1000P:
- huge jar of it for about the same price as 476s
- high temp property is a plus for my black car in the sun
- doesn't leave as much miscellaneous dirt on the surface after rain; seems to rinse cleaner naturally
I use FK1000p on my black car that sits outside in the south. However, I don't like having to be careful when applying it for trim. And it actually seems to dust a little bit, builds up in the crevices, etc. Leaves a very nice glossly look to the paint - hard to describe but others have done it already. A freshly waxed FK1000P car looks great.
476s - well you get a lot less than FK1000P, but let's be honest, a jar of it will last you many years doing your regular cars. I like that I can apply it to trim without worry. And I love the beading - it's like the water is afraid of the paint. 476s goes on my wife's daily driver, which is garage-kept. It lasts a loooong time - I have some on right now that I applied 11 weeks ago and it might as well have been 11 hours ago. As a plus, it seems to have some minor filling ability.
Overall I think I'd choose 476s between the two. But for $30, you could have both and probably 10+ years of wax supply for a couple of cars.
Unfortunately I didn't throw FK1000P into my current 8-way wax test. However, I'm going to split a car in half this summer and do a FK1000P v. 476s challenge whenever my current coat of 845 + FK1000P wears off.
