If you'll look over my posts again you'll see that I reccomended Zaino to him already. You're not presenting a dissenting view from mine, I stated that the statement that all carnuabas last only a few weeks is false and that Zaino will not always last 6 months, these are facts not opinions. Longevity is almost completely contingient on the environment, washing procedures etc. Zaino will usually last longer than a carnuaba but thats not always the case.
It is true that proper prep SHOULD include a swirl free exterior, but its oftentimes impossible to achieve a 100% swirl free exterior on a daily driver, especially if its a dark color. I take extremely good care of my car and it isn't 100% swirl free, maybe 90%. Nobody else on earth can see them but I can. Working constantly to remove all swirls does two things, it eats up your time and it constantly removes paint. 5,6,7 years down the line when the clearcoat starts to fail that will suddenly become a problem.
So, thats why I don't use Zaino or Klasse, I can get the paint to a good looking place without overly risking the clearcoat depth then I can hide whatever minor is left with a final polish and a carnuaba that makes it look perfect. When its nice I enjoy waxing so I usually throw on another coat of something every week or two. I have EX-P sealant x2 and Meg's #16 on my car for 6 weeks now and its holding up fine. Its supposed to be fine this week I'll probably throw on another coat of #16.
That said, if I had a silver car (which my next one will be) I'd definately use Zaino as its an excellent product. A miracle product though, or the best product its not. There are too many great products out there to call any product the best as they all have good and bad points, Zaino's no different.