Our partner brand, Duck Country Carpet Cleaning, did an excellent job in presenting this comparison between the hot water extraction method and the VLM Bonnet method.  You need to see this if you want to fully appreciate what advances in carpet cleaning have yielded for you, the customer.
The method we prefer the most is a Very Low Moisture method which cleans, traps dirt and the residue in a crystalline polymer for vacuum removal later on.  The carpet is dry in an hour rather than a day. This method utilize GREEN chemicals to lessen our impact on the environment.