I have used this.
If you go ahead, make sure you follow the instructions. It must be allowed to dry properly after application, if it rains or gets wet it will cause huge streaking. I found it of little use above the usual back-to-black products simply because things like APC, TFR, certain pre rinse products etc would strip it off, so I wasn't getting any longevity benefit from it due to the frequency of washing my car.
