I tried this today to clean a concrete parking pad that hadn't been cleaned in 12 years. I was using a Black Max pressure washer rated at 2700 psi and 2.3 gpm. I noticed striping, the washer wasn't cleaning well in the middle of the path. I checked the nozzle and one was plugged. That's the main reason I'm giving this 4 stars instead of 5. That should have been caught during manufacture. Once I fixed that, it worked better. You have to go pretty slowly but it's better than using a spray nozzle, even if you have to go over some of it again. It's very light and manueverable. We'll see how it stands up to extended use.
I bought this surface cleaner recently and did several sidewalks and a patio in literally 1/2 the time it took me to clean these areas just using the nozzle on the pressure washer. It does a nice consistent job effortlessly