Yea, a black car is verrry hard to keep looking good. You'll notice swirls on even new black cars that have been off the lot only a couple months. And the problem with normal polishes is that they're white, and if it gets into all the little crevises and stuff, it's going to take a lottt of detailing to get to it.
I've used the black polish (Turtle Wax Color Cure) and it works awesome, it covers up all the swirls and scratches pretty impressively. The only problem is that if evaporates very quickly... it looks good for about a week, then it starts looking back like it did before. The chipstik is also pretty good at covering up small chips on the hood.