I've used a Host machine , a Cert pile brush and a rotary to pre-scrub with in the "real world"
HANDS DOWN, a 70 to 90+ pound rotary blows them all away for shearing soil off the fiber.
The roll brush machines will dig out hair and such, but appearance wise, the roto scrub kicks their azz every time
as far as what pad/bonnet/brush to use?
"one size don't fit all"
On a decent cut pile, we'll use synthetic scrub bonnets saturated in pre-spray.
On a trashed loop pile olefin com, we'll use an aggressive VCT scrubbing pad.
My shampoo brush hasn't been used in years
Steve, why use an encRap juice to pre-scrub when you'll be rinse/extracting it back off?
It would be more effective and le$$ money to scrub your "regular" pre-spray
Dan, spray more pre-spray down when scrubbing or get there before it dries out.
If you're using a green VCT pad (VERY aggressive) i expect you'll find a "regular' shampoo brush to be lacking
..L.T.A.