My brother told me to get rid of him the first time he met it. Then, after it got to know him, he praised how good the dog was.
He scared the heck out of several people, but never bit anyone … but he left no doubt in your mind that he could have had you!
I could hike with him w/o keeping him on the leash, and he would stay close, and if I told him to "stay", he would, no matter what he saw. I would just leash him whenever anyone else was coming. He was good with most people, but every now and then he made it clear he did not like someone.