Bought a Rocky from Kevin, and used it last week on a Limestone restore we had booked in, and have to admit what a great piece of kit, with the right brushes and chemicals removed two coats of unknown sealer then honed the surface, even prior to sealing surface looked like new as stated by the home owners.
This may well be the way we now do all our natural stone cleaning, as I feel the clean could be a better and a cleaner clean then just pressure washing just seemed to give the paving that extra bit of oomph. It didn't really take that much longer to do either given the dwell time of the coatings removers.
So armed with the "Rocky" and a Karcher, plus a wet-vac this could be our new set-up.
Might be worth thinking about if you want to go to another level.
Photos of the job are on our Facebook site.