Any aggitation is better than no aggitation. Sebo is really light and easy to use but they are kinda on the bottom of aggitation ability. Next would be the host scrubber, these were used for dry powder cleaning and readily available on ebay and craigslist. And when you got an extra couple grand get the whittaker lomac type scrubber. The lomac is fast, looks professional and aggresivaly scrubs the carpet. Some people use rotary scrubbers which do scrub good but have others issues I don't care for.