What is your current grooming routine? Knowing how often you are grooming and which brushes you are using in what order would be helpful. You may not need any new brush at all - it's often more an issue of technique.
All of our horses LOVE this brush, even though it is used with a loud scary drill. Once it gets going they all stretch out and do the lip thing and cock their legs and just generally act like they are enjoying the super brush. LOVE this thing.
We have always used the same routine. Curry in circles, flick dirt off with a stiff bristled brush, and then remove finer dust with a soft bristled brush. If shedding, we add a slick'n'easy grooming stone to remove loose hair and additional dirt. If your problem is just dust too fine to remove, try wiping the horse down with a dryer sheet to reduce static.