Several years ago Consumer Reports rated Black Magic #1 so I tried it. It is fairly amazing stuff. It never really dries to a white "haze" so there is no white residue in cracks like most other car finishes I've ever tried. And it seems to be an extremely durable and "slippery' finish. Any kind of "soft water" spots on it, like from a clean rain, I can wipe right off with my California Duster and rarely even have to wash it with water. And it lasts easily for a full year before I put it on again. The only downside is that because it does not ever dry to a full white haze it takes a bit more effort to wipe off after it does dry and a few more towels. To me it's worth it and I'll keep using it.
My 2 cents.
Oh, here's the Black Magic:
http://www.blackmagicshine.com/wet-shine-liquid-wax.php
P.S. As per the instructions, the colder the surface the easier this is to work with. I usually put it on at the end of the winter while it's still cold but will be fresh enough finish to take me through the summer.