When you choose a commercial carpet cleaner, you want a company that has a truck-powered system. It gives much better results as there is a very powerful motor and a heater to keep the water hotter than you can get it. The operators should be certified and employed by the company you call, not contracted from other companies. The company should be IICRC certified as well. You should be able to get references, and you should get an exact and itemized estimate in writing.