I have used this product extensively with excellent results on my black car. I agree with the others that it does not last that long, but gives excellent initial results.
You can now find this product almost anywhere, including outlet stores like Sams/Costco/PriceClub, where it is alot cheaper than your average auto parts store.
Remember to spritz each panel with spring water prior to your final buff with a microfiber in order to evenly spread the product.
I usually use 3M imerial hand glaze prior to the zymol.
I am new to this forum, and it appears that there are other products that are more popular (like souveran/s100/etc). You might want to surf around and ask some questions.
I am familiar with this product, however, and have gotten better than average results.