i keep forgetting to pick some up to do a test with P21S GWC vs CG GWC .. but then again my wheels are always clean so i dont think i would be much help
i do believe i read that it works just as well as P21S
I've used CG Sticky Gel Citrus Wheel Cleaner. IMO it works very well. I've used it on a frineds F350 wheels that I thought were beyond cleaning and they came out like new. My complaint is that this is realy not a gel like I thought it would be. I thought it would be like the Fourstar Wheel Cleaner Gel I used before this.
I have the Citrus Blue Wheel Cleaner...and also sticky gel. Both are good..i like the citrus blue better though. i have it cut 1:1 with a foaming head sprayer and it is pretty safe and effective.. the sticky gel isnt much of a gel at all..i have it cut 1:1 and just a foaming sprayer so it will cling..it wont do much clinging without it i doubt.