The large hand brush ( a bit larger than a shower brush) has long medium-soft nylon bristles that seem to do something different than the orbitals. It reaches deeper into the pile. My hand brush action may be similiar to what the Cimex does, but alas, I don't have one of those.
I can loosen stubborn dirt with my hand brush that I cannot get up with OP, especially on BERBER. Of course I have to followup with OP to lift the loose dirt out. I will do areas up to 4 or 5 feet square with the hand brush, but of course I am not happy about encountering stains like that.
My customers are thrilled, but I am left wishing it were easier.