I agree 100%
P21S pretty good for what it is. The only problem with it is the price. It was probably the first "safe" wheel cleaner to hit the mainstream, or that's how I remember it at least. At the time there wasn't a lot of products out there like it, so I guess you were paying for the "safe" factor for your EXPENSIVE Porsche or BMW wheels.
Now its different though. AG sells 1000mls of P21S wheel cleaner (regular) for $19.99. Chemical Guys sells 473 mls of Sticky Wheel cleaner for $8.95. However, the CG product is dilutable 1:4, P21S is not.
It takes 200 mls of CG SWC to make 1000 mls of wheel cleaner. If you do the math, that's about $3.78. That's assuming you only by the 16 oz bottle. Of course, if you buy it by the gallon, its much cheaper.
So, for 1000mls of "safe" wheel cleaner you can pay $3.78 for CG's; or $19.99 for P21S. Both products will give comparable, if not identical results. For me, I just can't see spending the extra cash just to not have to mix a bottle. Also, if you use the CG product, there is no problem using the cleaner "liberally" as your not spending twenty bucks for a bottle. This may even help you clean better, as your not trying to conserve product.