I have used and compared both P21S (carnauba) and RejeX (synthetic) on both mine and my wife's cars. In my experience the RejeX produced and equal gloss and lasted MUCH LONGER AND COST A LOT LESS MONEY!!
Both cars were washed, clay bared, KlasicAIO'ed and then waxed. I had been using RejeX for some time and was talked into using the P21S which did not last 3 months
and have gone back to RejeX every 6 months whether the cars need it or not.
RejeX is the best I have ever used in my 50+ years of car care!!
