This picture was after an 800km round trip. My make of car is notorious for massive amounts of brake dust, so to put this in perspective, I was very pleased. Since then I've also tried PB's wheel sealant and like it quite a bit too - but the Michelin stuff is super easy to use.
the Michelin product works well, I've been using it for 3 months now. I think you get the most impact when you have very heavy brake dust. Certainly worth the $6 invesment to demo it on your own ride!