We use (pre spray)SPM if going/need to extract, as some jobs are better with extraction, but like I have said before, Dynamall with pad works a treat on most jobs alone, especially commercial carpets. We did a canteen area not long back, full of food, and tea, coffee stains. Pre sprayed with Dynamall, left to dwell for 5-10 mins, got the sprite out and job was a good one.
Very, very good results. The colour that comes back into the carpets after using dynamall is great.
It's only my personal opinion, but I know of more and more who are using this method of cleaning, and the repeat custom and recommendations on both commercial and domestic properties is worth its money in gold by cleaning this way.