Has anyone got the Karcher alloy wheel brush attachment and if so does it scratch the alloys when used?

I am looking for a good wheel brush and this seems to be the one

 

I havent heard of it till now but I did some research and it looks like a pretty good brush. I did a review on the Ace powerstick a couple threads down. My favorite brush ive used so far and ive tried about 10. It does very good at cleaning the spokes and inside of the rim. For the face of the wheel I use a boars hair brush and for the lug nuts I use a swissvax wheel brush. Try it out and let us know how it works.