As long as you are within 25 minutes of dumping site for branches and they charge less than $5 a cubic yard, it is cheaper and FASTER over the course of a year to buy a 14 ft trailer, load them yourself, haul them, pay the guy to dump and drive back than pay pay one guy to cut up a truck load of brush small enough to fit into the machine and another to feed the twigs through. A used 12" can literally do in 100 hrs what a 6" would do in it's lifetime.
Like using a Honda Accord to haul logs off a site. Seriously a waste of time.