I have plasti-dipped rims and got tired of having rims that still looked like brake dust even after washing. I was a little hesitant to try this stuff due to the cost but there were many great reviews so I pulled the trigger. I must say this stuff works. I have an M3 with massive brakes so break dust is a constant problem for me. After hitting my rims with a power washer, spraying them with soap and then rinsing, I sprayed this stuff on my rims. Let it sit for a couple minutes (out of the sun) and rinsed it off with the power washer. You can clearly see the difference in my before and after pictures. I tried applying the spray only and I also tried scrubbing the rims after spraying and the results were very similar. This stuff works with or without scrubbing and I highly recommend it whether you have dipped rims or not.
NOTE: The picture with the brake dust is AFTER power washing. So can see how ineffective washing alone is vs. using this spray.