Just wanted you to know that we are getting a lot of good use out of our Brushshark. We are using it in East Texas on yaupon holly, which is denser even than the mesquite/cedars in your videos.
It works great. Rather than simply cut them off (which of course it does well) we choose to grab the trunk with the teeth and pull it up roots and all. Keeps us from having to bushhog the regrowth in two years.
If anyone in East Texas wants to see one in action, have them call us.