advice on orbital surface cleaner

I got a Ryobi from HD but they all do the trick I'm sure. Just get one that's rated for the same PSI as your pressure washer, which most are pretty universal.

Just a little tip for driveway cleaning.
Get a bottle of pool chlorine (12% sodium hypochlorite).
Mix with water at 10% :1 part chlorine and 9 parts water and a splash of dawn.
Use a pump sprayer and pre threat the driveway
then pressure wash.
Just pressure washing doesn't get all the organic material in the concrete.
A month later when it rains you will see lines up and down the driveway.

I also do a post treatment spray to make sure all organic material is dead.
Your driveway will never have lines and will stay cleaner years longer.

And soak the side of the driveway with water to avoid chlorine burn to the grass.

Thanks for the responses. Ended up with this today LINK
I have yet to use it.