We have an Onyx Black Z66 built 12/01, and I've never noticed a problem with the paint. This is our second black vehicle, with our past 300M being Deep Slate, a sort of metallic charcoal black color. That was the first car we cleaned fully each week, but it was sort of an experiment. The paint on that car was thin, and the hood had quite a few micro chips after a year and a half. It had some swirls too, but that was mainly caused by me.
Now, with the Av, I know what I'm doing and use only the best, usually expensive stuff. I also have been operating a small detailing business this summer, so detailing is second nature. Currently, I have 13 coats of polish/sealant on our Av and always wash and QD weekly. In contrast to everyone else it seems, I've always had the impression that it has a high quality paint job, and even had someone comment on it saying "you can tell it has a very good paint job...looks like a show car without any orange peel or imperfections." I can also honestly say that there are virtually no swirls or scratches in the paint since purchase in March. No paint chips either.
A lot of cars have cheap, thin paint jobs anymore, a result of cost cutting. Your best bet is to take the best care you can, using only the best stuff that you can afford to protect & beautify your Av, especially black. Oh, by the way, I have 3 coats of Klasse All-in-One, 3 coats of Klasse Sealant Glaze, and 7 coats of Platinum Ultimate Paint Protection.