My rental unit had heavy stains and I was not impressed with this method of cleaning. While minimal water was used, there was no extraction of water and or dirt. The equipment merely had a circular motion that rubbed the stains around on a clean pad that was to soak up the stain but no real suction to remove it.
I believe I would not have had "like new" carpet with any method, but I won't use a vendor with this approach to cleaning again.