I've been using spot-n-boost the last few days. I've only used it as a spotter, not a booster. So far I am VERY, VERY impressed.
Just yesterday for example I had a customer beating me up on price. Told me he has never paid that much before,etc, etc. I didn't want to leave empty handed so I agreed to give him a "first time customer" discount so that he could see what my cleaning was all about and decide if it was worth the extra money for his next cleaning.
His carpet looked practically brand new, you could tell he cleans it regularly, except for one fairly large, dark, black spot. I asked him if he knew what it was and he said no but don't worry about it, it's been there for YEARS and no one has ever been able to get it out. He had mentioned he cleans his carpet about every six months. I told him I'd see if I could do anything but no promises. My helper applied a little spot-n-boost to the spot and rubbed it in with his shoe and tells me the spots gone. By the time I got to extracting that area I couldn't even see where the spot originally was.
The customer ended up paying me my original price and went on and on about how this was the best cleaning he's ever had and I ended up scheduling the neighbors house before I left. I believe this was mostly due to that one spot coming out.