Blue magic is pretty good stuff, especially at the price. I do think that the P21S is stronger, but it is more expensive. I used both on a '68 Olds Delta to getting pitting and stains up off the bumper. It was a lot of work, but the P21s worked perfectly! The Blue magic miught work better for something newer and not in such a state of disrepair. Like maintaining a good deep polich on a motorcycle, a truck w/ chrome, or a newer car's chrome.
:up