what would you expect him to say. I have used everything he sells, Z6 has always been a dust magnet which is why he always says it is a repel ant. He owns the company and is a marketing genius. He has created a cult following for a friggin car wax product.
I use FK425 - by far the best QD I have ever used. In addition to doing a far better job than any others, it will not attract dust. I have (among others) a white M3. With Z^ the rear end is covered in dust in 1 day. With the 425 it is a non-issue. This has been talked about extensively and other than the Z-ealots who see Zaino as the next coming and thus can do absolutely nothing wrong, most others know Z6 attracts dust.
Try an OTC QD and see the difference immediately. Then, try FK425 - you will never go back to zaino imo.