I have always wanted to try Zaino, and many black car fans bow down to Zaino, but I'm not so keen on paying over $100 for everything.
I have used Zymol, Turtle Wax, Gold Class, and Eagle One Nano Wax. Of any that I used, I got a very good shine from Zymol, and was very disappointed in Gold Class. It was hard to apply and a hell to remove.
I picked up some Nano Wax several weeks ago and used it on my 00 Silver Grand Am, which, as some of you may know, was the last year for the more flat silver color before the Galaxy silver replaced Silvermist, and it gave my GA GT a shine that two coats has protected up until this day. I wash it, and it looks like I just waxed it. It's amazing.
I also used the Nano Wax on my Firebird, and while it didn't completely "remove" all the swirl marks, as it's a black car, it definately made the paint look wet and svelt.
DEFINATELY would recommend Nano Wax for those who like decent beading protection, and a massive shine on just about any color.