I have been trying to figure out which CRB to buy. I've looked at the brush pro and the duplex 420. It is kind of cool that the duplex 420 also picks up some of the moisture on the ground, but I have seen the brush pro in person and does a great job of picking up hair and rocks off of the ground and putting it into the trays. I haven't seen the duplex in person, but was wondering if it does just as great of a job at picking up rocks and hair, also which of them has longer lasting brushes? Any other CRB suggestions would be greatly appreciated. Thanks!