When selecting a carpet scrubber, the primary differentiator is the motor power and tank capacity. For commercial use, prioritize machines with dual-motor systems (one for the brush and one for suction) and a tank capacity of at least 10-15 gallons to minimize downtime. For residential or light-duty applications, a compact, upright design with a rotating power brush is sufficient. Ensure the machine offers a high-pressure spray (at least 100 PSI) to penetrate deep into carpet fibers for professional-grade cleaning.